ECD Architects Blog :: ECD Architects

ECD at Ecobuild

Fri, 11 Mar 2011 16:55:45 +0000

Another year, another Ecobuild, new venue, new chapter. The switch to Excel will no doubt be hailed as a success and the organisers will cite more exhibitors, more seminars and more visitors as their yardstick. But as others have suggested, it felt like there was something lacking at Ecobuild this year. The journey over was surprisingly trouble-free though and afforded a panoramic view of our Ferrier Point tower block retrofit in Canning Town to the north of the DLR.

ECD’s Ferrier Point retrofit is the kickstart for the wider Canning Town regeneration development.

I am very lucky in that my role allows me to visit Ecobuild as much as I feel necessary - I have also been asked to speak at each and every ‘event’ since the first. So when you spend as much time wandering around those giant halls as I tend to, it is useful to have landmarks by which to navigate, just as in any urban environment. Ecobuild definitely started life in 2005 with a village atmosphere but it has quickly achieved city status but it was quite a different city to the last event at Earl’s Court. Gone were the open arenas in the heart of each hall, which had previously acted as public squares allowing visitors to drop in or drop out of the main plenum sessions as your journey permitted. Instead, the main conference was confined to a glass box ‘service station’ in the middle of the boulevard dividing the two halves of the city - I confess I never felt the inspiration to venture near the place. Forget the ‘public realm’, cram in more commercial outlets was the message. The usual landmarks were present – the 2-storey UKGBC hub, a SomethingZED building, a giant timber pavilion – but this city did not have the character of its previous incarnations. Whole quarters had been redeveloped for single technology suppliers – for example the PV ghetto in the north hall, where I felt I had to march through purposefully, averting my eyes from the monocrystalline merchants on either flank, lest they try to convince me their ‘SunEcoEnergy’ module was far superior to the ‘SolarEarthPower’ module over on their competitor’s stand! And since when did so many fashion models become experts in photovoltaic modules?

In any city, it’s nice to have a place to call home where you can touch base before heading out into the world. For me, I gravitated back again and again to friends at the Passivhaus Trust stand or the Green Building Store. The local landmark here was a new one – the UK Sipshouse Passivhaus mock-up, which I found to be a bit of disappointment. I just think it’s a shame that people will leave Ecobuild thinking that Passivhaus is about EPS sandwiched in OSB when it is about so much more. I did check that the SIPS had been upgraded from the usual components to incorporate thermal-bridge-free edge beams but even this was not really emphasised in the stand.

SIPs need insulated box beam perimeters to achieve the necessary psi value for Passivhaus.

Sticking with my ‘exhibition as city’ theme, I did enjoy the more bohemian quarters – the market places of the Natural, Traditional, Sustainable showcase, the Green Shoots bazaar and the TSB Innovations stands. At the latter, I caught up with Katy Duke from the Thermal Blind Company, taking a break from making fittings for some our retrofit projects, ideal where conservation constraints prevent triple-glazed window upgrades. Elsewhere it was great to see so many more Passivhaus-standard windows becoming available in the UK – a crucial component that is always under pressure to be substituted with inferior alternatives. This one from Green Building Store, the Alphawin , was well presented in a timber-framed wall mock-up.

The Austrian Alphawin window has impressive Uw and g values.

I also liked the idea of Porotherm T7 Perlite blocks – a robust, breathable clay masonry component that can achieve a solid wall U-value of 0.15 W/m²K or more with the minimum of external insulation, can be laid rapidly with almost no wastage and exceeds all acoustic and fire protection requirements.

The Isoquick raft foundation is another component I think may come in useful when trying to eliminate thermal bridges at the floor/wall junction – I look forward to the benefits of its speedy construction times and high thermal performance on future projects.

I noted a few big name absentees from the show with whom I had been hoping to drop in on to see new products I had heard about – Rockwool and Levolux to name a couple. Were there others missing I wonder? It would seem not given the sheer size of the event now. One unusual distraction for me this year was the opportunity to take a client around ‘shopping’. It was great to be able to show her planted roof options, window or door options and to be able to introduce her to the person designing her heat recovery ventilation system so that he could explain that we weren’t joking when it needed plenty of room and a good deal of early planning. It would be great to do that every year with ever client – my wife tells me that this is exactly how designers choose specifications in China.

The one aspect of Ecobuild that is never a let down is the chance to catch up with familiar faces with whom you usually only converse via email or twitter. Everybody journeys to Ecobuild at some point and with luck you will bump into many of them along the highways and side streets of the exhibition or at one of the many excellent (and free) presentations to be enjoyed. But the subordination of the seminars to the trade fair rankles – those narrow, mile-long corridors with blank partitions to each room meant that attending something that potentially involved very exciting subject matter was a rather bland experience. On the plus side though the technology worked faultlessly (always a plus side when you turn up with your presentation on a memory stick 30 seconds before you’re due to start) and the seminars seemed to be very well attended. The interesting seminars on Passivhaus and retrofit were quite often billed as ‘fringe’ though – when the event is called Ecobuild, why is it that ex-pop star particle physicists and fashionistas get top billing, whilst all those hardworking designers who have given up their free time to share their experience of actual eco-building (ie the bit that make the event the draw it is) are not deemed worthy of so much as a link to their website? And sorry to keep on but I have one more moan. The exhibition layout on the Ecobuild website was excellent, with all the exhibitor stands clearly named to help find your way to a particular destination. The hard copy one handed out to visitors however was next to useless. Unwieldy and lacking labels, it required constant folding and unfolding to get the reference code for a particular exhibitor and find on the map on the other side – it annoyed me constantly. But I’ll still be back next year.

Retrofit Project Diary: 13 Joyce Avenue - Blog 1

Mon, 24 Jan 2011 09:59:58 +0000

13 Joyce Avenue

Blog 1 (24.01.11)

United House Contractors www.unitedhouse.net started work started at 13 Joyce Avenue in early December with initial work focussing on asbestos removal, site strip out and scaffolding of the front and rear elevations completed. In order to avoid a stepped flashing at the party wall we also obtained the neighbours consent and planning approval to insulate behind the existing wall hung tiles to their property as well. A number of the long lead-in items (i.e.: triple glazed windows and vacuum insulated panels to external walls) are currently on order and in the meantime works are progressing internally. 1^st fix electrics are complete with British Gas due to install the Micro CHP unit and radiators in early February.

The innovations on this project include the use of Vacuum Insulated Panels (VIP) to external walls. These products achieve extremely low U Values (see: www.nanopore.eu ) but need to be carefully designed to ensure that fixings do not compromise integrity, i.e.: it is not possible to mechanically fix through the vacuum! Future maintenance and tenant use also needs to be carefully considered as a satellite dish or hanging basket fixed through the insulation would also compromise performance. This product has been used in the refrigeration industry but never before in construction. The VIP’s are currently on order as each panel needs to be individually sized to suit the installation – No cutting on site is possible!

Photographs show the new platform in the loft to receive the MVHR unit and the proposed loft hatch being assembled. The project is currently due to complete at the end of March with a planned open day on 16^th February. This property was until recently void and the client (Enfield Homes) is taking the opportunity to upgrade the property to ‘Decent Homes’ standard including a new bathroom and kitchen

Retrofit Project Diary: Warnham Road - Blog 4

Mon, 17 Jan 2011 16:29:12 +0000

Timber frame, 22/12/10 By Ruairi Kay

The front and rear infill panels have been removed and most of the new timber frame has been installed. The build up for the frame is: plasterboard and skim finish, Intello plus vapour and air barrier, 125mm deep timber frame with Celotex PIR insulation tightly fitted between. This is then finished with ply. In the new year Walltec, (the external wall insulation sub contractor), will then fix 60mm Phenolic insulation over this, finished in a silicon render. Overall u-value is 0.13 W/m²K. The concrete panel elements will be clad in vacuum insulated panels, more about this in the new year.

The rear elevation with new timber frame and most of the windows fitted

We have had some problems with the window and doors fitting the openings on site on this project as well. It appears that the timber frame installation differs from what was originally designed, resulting in a smaller opening in two incidents. We have however been able to switch the windows around, meaning we only need to re order one of the windows.

The front elevation

Retrofit Project Diary: Warnham Road - Blog 3

Mon, 17 Jan 2011 16:26:06 +0000

Windows arrive, 09/12/10 By Ruairi Kay

The excavations below ground are now complete and we found on the corners we could not go as deep as we wanted as there are concrete pads about 200-300mm below the surface that support the concrete cross panels. Also on the gable the ground floor slab cantilevers over the foundation wall, so we will need to cut this projection off to allow the external wall insulation, (EWI) to run below ground level. As much as we prefer to specify EWI over IWI, things like this highlight the fact that it is not as straight forward a solution as some people like to think and comes with its own set of problems, different but equally challenging to those encountered when internally insulating.

Excavation below concrete cross panels

Not much else has happened on Warnham Road since my last visit. The new windows are onsite now and we have finalised the timber frame design so this will all start going up shortly.

Retrofit Project Diary: The Birches - Blog 4

Mon, 17 Jan 2011 16:24:33 +0000

Spacetherm Dry-Lining, 22/12/10 By Ruairi Kay

Installation of the Spacetherm dry-lining is well underway over the existing cavity wall. This is supplied by A Proctor group in Scotland. Their normal build up for this kind of project, (which has been tested by the BRE!) is to fix Spacetherm F (aerogel laminated to Fermacell board with an integrated vapour barrier) to timber battens fixed to the existing wall. In this case the depth of aerogel is 60mm to give a U-value of 0.15 W/m²K. We have concerns about this kind of build up in relation to airtightness and moisture management, especially after speaking to Niall Crosson of Ecological Building Systems at the annual AECB conference back in October. The problem with this system is that you are relaying on a butt joints between the boards for integrity of the vapour barrier. As the vapour barrier has been laminated between the Fermacell and aerogel it is impossible to tape or check the joint. So even with extreme care on site you will end up with breaks in the vapour barrier at joints, added to the difficulty sealing around service penetrations. Due to a temperature and pressure difference between inside and outside, (particularly in winter) warm moist air will be drawn through these gaps to the existing wall behind. This will increase the heat lost from escaping warm air but more worryingly may allow moisture to condense on the existing wall behind the insulation leading to a higher risk of mould growth. So, we have worked with A Proctor to design an alternative laminate for this and a few of our other retrofit projects. Instead of bonding the aerogel to Fermacell we asked them to laminate it to 9mm ply. We then fix this build up directly to the wall. The ply allows gives a firm ground for the fixing and also creates a base for the Intello Plus vapour and air barrier that is laid over it. This arrangement gives us the opportunity to seal and check the vapour and air tight layer before we apply any finishes. The elimination of the void behind the boards removes any space for air to circulate and for mould to grow. We then fix timber battens over this to create a service void and finish with plasterboard and skim.

Spacetherm dry-lining

Fixing the boards has not been without its problems. We discovered that the inner leaf of the cavity wall is constructed of hollow blocks, making it difficult to find a secure fixing. The contractor suggested we first fix timber battens to the wall then fix the boards to these with the aerogel notched around them. We were not keen to use this method and have put them in touch with Hilti about an alternative fixing. The guys on site are also finding the aerogel particularly nasty to work with and cannot wash the dust off anything. Given the choice, none of them would work with it again!

One of the guys on site, well covered to avoid the dust, but still got it on his eyebrows!

Retrofit Project Diary: The Birches - Blog 3

Mon, 17 Jan 2011 16:21:18 +0000

Windows arrive, 09/12/10 By Ruairi Kay

The windows have arrived and are being installed on site now. The windows we have chosen for this project are EcoPassiv triple glazed windows from the Green Building Store. The thermally broken frames are made from Forest Stewardship Council (FSC)-certified timber. The argon filled triple glazing with warm edge spacers gives a whole window u-value of 0.75 W/m²k. Looking at windows that have been installed beside the old PVC ones, one thing that is immediately obvious is the frames are quite wide. Triple glazed windows do in general have fatter frames to accommodate the thicker glazed units and thermal breaks within the frame. In this case we have also had to increase the frame size to avoid any clashes between the internal insulation on the reveals and the inward opening hinges, which were located very close to the edge of the frame. However we have simplified the mullion and transom arrangements on the new windows to compensate for the larger frames and ensure sufficient day light levels. The tolerance gaps at the cills of the installed windows also look a little on the large side. As this is a brick faced building that we are insulating internally we do not have much opportunity to cover gaps left on the outside, especially as we had planned to keep the tiled cills. Possible solutions maybe to add another course of tiles to the cills to hide the gaps or alternatively to use aluminium cills.

EcoPassiv window installed

Retrofit Project Diary: Hasting Road - Blog 5

Mon, 17 Jan 2011 16:20:05 +0000

Internal wall Insulation and Micro CHP 22/12/10 By Ruairi Kay

The internal wall insulation to the rear extension is now mostly complete, except the bathroom wall that needs to be left off until we seal up the existing manhole. The existing brick cavity walls have been lined internally with 70mm Celotex. We originally specified Spacetherm here like the first floor, but we changed this to Celotex to help bring the project back on budget with a minimal drop in performance. The savings is approximately £3000, over a small area of wall. On top of the Celotex we have fixed a layer of ply, to give a firm backing for the Intello plus vapour and air barrier. Then we fix timber battens to create a service void and finish this with plasterboard and skim.

Dry Lining to the rear extension.

British Gas have started to install the Baxi Ecogen Micro CHP and new wet radiator system. CHP, (combined heat and power or cogeneration) is the process of producing both electricity and useful heat from one source. Large scale CHP has been around for some time, but reliable micro domestic models are only starting to become available. The Ecogen unit produces an output of 1kW of electricity while providing 6kW of heat via a free piston Stirling engine. An addition output of 18 kW can be provided via a supplementary burner with no electricity generation. An addition output of 18 kW can be provided via a supplementary burner with no electricity generation. At the design stage we had difficulty getting estimations from Baxi as to how much electricity per year the unit would generate in this case, so in the end we used our own formula. Using our annual space and domestic hot water requirements from PHPP (PassivHaus Planning Package) and a series of assumptions on boiler operation we have come up with a figure of 698 kWh per year electricity generation. The monitoring phase of this project we will give us vital information on how the unit actually performs.

Retrofit Project Diary: Hasting Road - Blog 4

Mon, 17 Jan 2011 16:18:47 +0000

Window Problems, 16/12/10 By Ruairi Kay

Since my visit last week most have the windows and doors have now been installed, but not without problems! On the rear brick extension it appears that the main window into the dining room has been manufactured too small. Once the window was installed the gap around the frame became very obvious, and as the extension will be insulated internally there is not much opportunity to hide these gaps unless we render the whole rear extension externally as well.

Window to rear extension

The front door is also too wide for the opening. It was not possible to measure ehe existing structural opening when the original window survey was undertaken, and it seems that a due to miscommunication this was not later confirmed. We are trying to get to the bottom of what went wrong but given the long lead-in time to order replacement windows we are currently discussing other options to accommodate these discrepancies with Wates and Green Building Store, who surveyed the openings but did not fit the windows as was originally intended. A site meeting between all parties is now arranged for the first week in January.

Taped window to the main house

Internally the first floor is now been fully lined internally with 30mm aerogel laminated to 9mm ply over the mansard roof and Celotex insulation between with an Intello Plus membrane and battens over to create a service void. Unfortunately and strongly against our advise Wates have pushed ahead and fitted the plasterboard lining to this area before doing an intermediate air test. This will make it extremely difficult to find and rectify any leaks in this part of the building later. This highlights the problem of trying to fit an intermediate air test or even the principles of air tight construction in to a normal construction program. Maybe we could have been clearer about the requirement to complete and test the air tight layer before covering it, but with such a tight program it seems difficult to arrange.

Airtight layer courtesy of the main contractor before it was covered up

Finished window reveal upstairs

Retrofit Project Diary: Hasting Road - Blog 3

Mon, 17 Jan 2011 16:15:06 +0000

Blog 3: Windows and hidden manholes, 09/12/10 By Ruairi Kay

The windows we have chosen for this project are EcoPassiv triple glazed windows from the Green Building Store. The thermally broken frames are made from Forest Stewardship Council (FSC)-certified timber. The argon filled triple glazing with warm edge spacers gives a whole window u-value of 0.75 W/m²K. Fitting the windows on the concrete frame part of the house we have discovered old concrete cills below the pressed metal cills that were previously installed. This means the windows are a little shorter than required, but with a carefully chamfered packer they should work fine and the external wall insulation will overlap the frames and cover this detail anyway.

Side view of house

We have discovered a manhole located internally in the bathroom of the ground floor extension underneath where the shower used to be! On a closer inspection it has 5 connections including the neighbouring house. This presents a problem as we plan to insulate the floor over the manhole, it’s so close to the wall that even if we could leave an access panel the new internal wall insulation would overlap it and the new shower is going back on top of it anyway! The building control officer was on site today so we have managed to come to an agreement that does not involve digging the floor up and laying new drainage. We will provide new rodding points so the manhole can be rodded from each connection, then we will construct a special cover to sit on top of the open pipes and prevent any blockages from filling up the manhole, which is quite deep. Essentially we will create a sealed junction. We are going to use a steel plate for the cover, welded to support angles on the existing brick. Then we can cover in above and lay the new floor etc.

Manhole

Retrofit Project Diary: St. Joan Close - Blog 8

Mon, 17 Jan 2011 16:09:20 +0000

Meters, 22/12/10 By Ruairi Kay

Not much to report here other than the new electric and water meters have been installed and the internal decoration is being finished off, still waiting for the windows to arrive though..... In order to fulfil the monitoring requirements of the project we need to install new electric, gas and water meters with a pulse output. Normally the various utility companies would be engaged to replace the existing meters. As utility companies are notoriously difficult to deal with it, we felt it would be unlikely we could have the meters changed within the tight program. So we have purchased our own meters with a pulse output and fitted these in series with the existing meters. We have also created a new cupboard to contain the existing meters, new meters and the Wattbox data relay unit. The Wattbox is an innovative heating controller that monitors occupancy and heating preference and uses this information to constantly optimises the central heating and hot water to maximise comfort and efficiency. In this case it also takes care of all the data acquisition required by the Energy Saving Trust as part of the 2 year monitoring, more on all this in a future post.

New meters for electric, CHP output and PV output.

Retrofit Project Diary: St. Joans Close - Blog 7

Mon, 17 Jan 2011 16:05:54 +0000

Baxi Ecogen and Building Control, 09/12/10 By Ruairi Kay

British Gas were onsite today installing the Baxi Ecogen Micro-CHP and new wet radiator system. CHP (combined heat and power or cogeneration) is the process of producing both electricity and useful heat from one source. Large scale CHP has been around for some time, but reliable micro domestic models are only starting to become available. The Ecogen unit produces an output of 1kW of electricity while providing 6kW of heat via a free piston Stirling engine. An addition output of 18 kW can be provided via a supplementary burner with no electricity generation. At the design stage we had difficulty getting estimations from Baxi as to how much electricity per year the unit would generate in this case, so in the end we used our own formula. Using our annual space and domestic hot water requirements from PHPP, (PassivHaus Planning Package) and a series of assumptions on boiler operation we have come up with a figure of 455 kWh per year electricity generation. The monitoring phase of this project we will give us vital information on how the unit actually performs. The install looks good though I am suspicious the cylinder supplied does not have 80mm insulation as per our requirements. Some trawling on the internet office confirmed my suspicions. When I initial contacted British Gas about this they claimed that they cannot get a cylinder with anymore than 50mm foam insulation and that beyond that it’s not worth adding anymore anyway! This is contrary to what I believe to be true after seeing a good presentation on the efficiency of hot water systems by Alan Clarke and Nick Grant at Ecobuild this year. This has now been resolved and the correct cylinder will be installed on this project and our 3 other retrofit projects in Crawley.

The Baxi Ecogen

We also had the Building Control officer onsite today to inspect the work. His main concerns were; the effect of the increase of 28mm on ground floor (from the Spacetherm C insulation) where the floor meets the first stair rise, the new drainage and insulation works below ground and the loading of the new plant deck in the attic. He was happy with all the work he saw, though the below ground work had all been backfilled before he got a chance to visit site. Good we have lots of photos I can send him!

Retrofit Project Diary: St. Joan Close - Blog 6

Fri, 10 Dec 2010 17:14:29 +0000

Blog 6: Client Visit 25/11/11, by Ruairi Kay

Today we were joined by client representatives from Crawley Homes and Crawley Council for a tour of our 4 retrofit projects. Things are progressing well at St Joan Close. The external wall insulation is all up and has had a base coat of silicon render plus mesh. We have had to leave the insulation off the windows reveals, as well as the finish coat, until the new windows arrive. Ideally the windows should go in before the application of the EWI with an intermediate air test undertaken at this stage. Unfortunately we do not have this luxury as the window order was placed late and there have been some delays with delivery. The lesson here is to ensure you order your windows well before you start on site.

Client, contractor and design team with New PV in the background

On the roof BG Solar Technologies have installed the 8 Sharp 175Wp photovoltaic panels (a combined output of 1.4 kWp) which have an expected annual generation of 1180 kWh. They should make a valuable contribution to the properties electric supply and are expected to generate £ 487 income from the Feed-in Tariff scheme.

New PV panels

Inside, new kitchen and bathrooms have been installed to comply with the Decent Homes Standard. Recessed LED downlighters have been fitted to the ground floor ceiling. At first floor we are relying on the existing ceiling to form part of our airtight layer so we are using pendant fittings with CFLs which will be easier to seal and make airtight.

EWI to the neighbouring property

Retrofit Project Diary: 31 Twyford Road, Ilford, London

Tue, 30 Nov 2010 17:58:09 +0000

Blog 1: Twyford Road on site, 30/11/10 by James Traynor

After an initial delay, works have now fully resumed at Twyford Road with anticipated completion in late February. Following our regular site meeting last Friday it was confirmed by the Main Contractor (Breyer) that the Internal strip out (including asbestos removal) was now complete.

Photographs show the underside of the existing roof exposed with NBT ‘Pavaclad’ (wood wool) insulation stacked prior to installation on internal face of gable walls/ chimney and between rafters. The underside of the trusses will be lined with OSB to provide an air-tight envelope and battens fixed below to form a void for LED light fittings. The attic will then receive blown Warmcell (recycled newspaper) insulation between joists and ‘Pavatherm’ (wood wool) above.

On the ground floor the existing floor finish has been removed with ‘Frameshield membrane laid over existing joists and voids filled with ‘Warmcell’ insulation. This is then overlaid with 22m chipboard and sealed at junctions with Siga tapes to provide an air-tight envelope. (see photograph showing edge detail at solid floor). The property has now received scaffolding to all elevations in advance of the overcladding to be carried out in early January. This will comprise NBT ‘Pavaclad’ laid over a parge coat with a decorative render finish.

This property was until recently void and the Housing Association client (East Thames Group) is taking the opportunity to upgrade the property to Decent Homes standard including reorganisation of the bathroom and kitchen.

Retrofit Project Diary: Hasting Road - Blog 2

Thu, 25 Nov 2010 15:11:51 +0000

Blog 2: Strip out, 25/11/10 2010 by Ruairi Kay

The strip out of 22 Hasting Road is now complete and the main work is starting. The plasterboard lining has been removed from the inside of the mansard roof along with the existing mineral wool between the timber frame. This had been packed to the full depth of the frame allowing no gap for ventilation behind the felt. The guys on site have been carefully cutting sheets of Celotex and fitting them between the studs with a 50mm gap left behind for ventilation. All gaps are filled with expanding foam and all joints foil taped. Once this is complete we will fix Spacetherm insulation over the inside of the frame, (30mm aerogel laminated to 9mm ply) then a Pro Clima Intello plus vapour barrier and airtightness membrane followed by 25mm softwood battens, to create a service cavity, and plasterboard finish.

Plan detail of Mansard roof insulation

Mansard roof partly insulated

On the ground floor we will be removing the existing 50mm external wall insulation to the main house, (concrete post-and-panel construction ) and replacing it with 220mm Rockshield EWI. The rear extension (cavity wall construction) was to be dry-lined with Spacetherm originally similar to the first floor. However, in order to reduce cost and help bring the project back on budget this has been changed to Celotex. As Celotex does not perform as well thermally as the Spacetherm, we have used thicker boards keeping the performance drop to a minimum but the cost savings are still significant and therefore worthwhile.

Retrofit Project Diary: Warnham Road - Blog 2

Thu, 25 Nov 2010 15:10:15 +0000

Blog 2: Work Starts, 25/11/10 by Ruairi Kay

The strip out of 33 Warnham Road is now complete and the main work is starting. The property is system built using concrete panels with timber frame infill. In plan the terrace is made up of pre cast concrete I sections forming the flank and party walls with timber frame infill panels to form the front and back elevations and contain the windows. The retrofit package involves removing these infill panels, which are in poor condition and in some cases rotten. These will be replaced with new prefabricated insulated timber frame panels then all the walls will be over clad with a bespoke vacuum insulate panel external wall insulation system, more on this in a future blog post.

Existing Pre cast panel with steel beam over windows

Retrofit Project Diary: The Birches - Blog 2

Thu, 25 Nov 2010 15:08:12 +0000

Blog 2: Strip Out and Work Begins, 25/11/10 2010 by Ruairi Kay

Like Hasting and Warnham Road, the strip out of the Birches is now complete and the main work is starting. First fix electrical has been done and the guys on site are currently constructing the plant deck in the loft. These needs to be suspended 400mm above the existing joists to allow for the new 450mm Rockprime loft insulation and will support the heat recovery ventilation unit and invertors for the photovoltaic panels. In the kitchen, a new soil stack has been installed as the existing one was too close to the external wall which we plan to dry-line. When we removed the existing pipe we found it was connected to an old clay pipe in the kitchen floor. So we have now had to dig a large hole and replace the pipe run as far as the nearest external manhole.

Temporary support to the widened door opening

Retrofit Project Diary: 3 Seymour Street, Cambridge

Thu, 25 Nov 2010 10:53:26 +0000

3 Seymour Street

Blog 1 (25.11.10)

This project is slightly ahead of programme with all finishes removed and underside of roof boarding complete. The floor insulation (spacetherm) is currently being laid and wall insulation is due to follow on shortly. Following our fortnightly site meeting on Tuesday we made an inspection of this tiny (37Msq) almshouse property owned by Cambridge Housing Society.

Photographs show the underside of the existing roof lined with OSB and taped at junctions with Pro-Clima sealants/ adhesives to provide an air-tight envelope. The property was in fact even smaller when originally built in 1914. A flat roof kitchen extension was built at the rear (date unknown) of cavity wall blockwork construction. This is also being insulated internally as well as within the cavity.

This property was until recently void and the client is taking the opportunity to upgrade the property to Decent Homes standard to match the ongoing works in adjacent properties. This propert is due to complete in late January 2011.

Retrofit Project Diary: Gaymer Memorial Cottages - Blog 1

Thu, 25 Nov 2010 10:38:03 +0000

4 Gaymer Memorial Cottages, Attleborough, Norfolk

Blog 1 (30.08.10)

The ECD retrofit project, Gaymer Memorial Cottages project in Attleborough, Norfolk for the TSB started on site at the end of August and is due to complete in January 2011.
Works include: New heating system via ASHP with SHW panels; New high performance steel windows (to match existing crittall); High performance aerogel insulation as dry-lining to walls and solid floor; super-insulated attic; LED lighting throughout; photovoltaic panels and MVHR system. In addition this void property will be upgraded and remodelled with new kitchen and bathroom incorporating low flush WC, aerated taps and recycled kitchen units with A++ rated appliances.

Picture 1 (left) the Project team including from left to right Darren Cruice (Hastoe HA) Clare Hendry (Hastoe HA, Mrs Lawrence (tenant), Alan Potter (Roalco – main contractor), Kevin Walker (Roalco).
Picture 2 (right) future tenant, Mrs. Lawrence selects finishes.

Retrofit Project Diary: St. Joan Close - Blog 5

Fri, 12 Nov 2010 15:03:39 +0000

Blog 5: External Wall Insulation Starts, 12/11/10 by Ruairi Kay

This week’s site visit to Crawley also involved a trip to the other 3 Retrofit For the Future projects we are undertaking with Crawley Homes and Wates Living Space, see separate blog posts for more info. At St Joan Close it was nice to see some of the airtightness problems highlighted in the last blog post put right.

Sealing the electrical penetrations at first floor ceiling and wall to floor junction at ground floor

Externally the scaffold is erected and Walltec have started to install the Rockshiled external wall insulation. As a planning condition, this will also extend to cover the neighbouring property, no 11 St Joan Close. The parge coat has been applied to the front of the property and as you can see below the back garden is full of bales of Rockwool!

220mm deep Rockwool (100+120mm slabs) ready to be installed.

Retrofit Project Diary: Gaymer Memorial Cottages - Blog 2

Wed, 10 Nov 2010 14:49:47 +0000

4 Gaymer Memorial Cottages, Attleborough, Norfolk

Blog 2 (25.11.10)

Things are progressing well at Attleborough with completion anticipated in early January (1 week behind programme). The site is very busy at the moment with several trades onsite this week including plumbers; window fitters; electricians; MVHR and PV installers, etc. 1^st fix electrics and plumbing are ongoing with installation of PV due later this week.

Following our fortnightly site meeting on Tuesday we managed to give the future tenant (Margaret Lawrence) a guided tour of the property and explained progress to date:

Existing finishes have been removed and 80mm spacetherm insulation fitted to existing floors and external walls. The insulated wall build up receives an air-tight membrane and battens to create a service void for cables/ pipes thereby improving long term flexibility and minimising future risk of puncturing the envelope. Photographs show the underside of the existing roof lined with OSB and taped at junctions with Pro-Clima sealants/ adhesives to provide an air-tight envelope.

We have come across a few technical issues which have required minor amendments. These include the discovery that the property is in fact cavity rather than solid wall construction! We will of course be injecting insulated cavity wall fill to all areas which will further improve the already impressive U values of 0.15. In addition the short length of existing flex to the original meter means that we have been forced to reduce the thickness of wall insulation behind this small area.

This property was until recently void and the client (Hastoe Housing Association) is taking the opportunity to upgrade the property to Decent Homes standard including relocation of the bathroom and reorganisation of the kitchen.

Retrofit Project Diary: The Birches - Blog 1

Wed, 10 Nov 2010 14:18:49 +0000

Blog 1: Introduction, 1/11/10 by Ruairi Kay

14 The Birches is a 1950’s end of terrace property which has already undergone ‘Decent Homes Standard’ improvements. Works such as window replacement and loft/cavity wall insulation have previously been carried out in a piecemeal fashion and have resulted in a property that is satisfactory for living in. The house is built in a traditional cavity wall construction, with timber facias, plastic gutters and concrete roof tiles. Heating is by a wet system from a boiler with a first floor water storage tank. As one of 9500 houses in the ownership of Crawley Homes and over 60,000 units in the New Town of Crawley, this exemplar building could pave the way for many future sustainability retrofits. This is one of four retrofit schemes ECD Architects are carrying out for Crawley Homes in Crawley, East Sussex, started on site the October and is due for completion in January 2011.

Front of the property pre retrofit

ECD, Crawley Homes and contractor Wates have worked closely with the residents throughout the design period to ensure that minimal disruption is caused to the returning tenants. The retrofit package will consist of aerogel insulated dry lining, 450m of loft insulation, replacement triple-glazed windows, insulated entrance door, whole-house heat recovery ventilation and a micro-CHP boiler replacement, supplemented by roof mounted photo-voltaic cells. In addition, 100% LED replacement lighting is proposed to minimise electricity consumption, together with A++ rated appliances and advice to the tenants on how to minimise fuel consumption whilst maintaining adequate comfort conditions.

Passivhaus Design – Ventilation, Certification and Justification

Thu, 04 Nov 2010 09:53:15 +0000

Of all the characteristics of low energy dwelling design in the UK, the most emotive of all seems to be the ventilation strategy. The combination of an apparently innate hostility towards mechanical ventilation and a bloody-minded determination to live in draughty buildings has seen the UK fall way behind the likes of Germany, Scandinavia or Canada when it comes to understanding best practice in the design and installation of heat recovery ventilation. Perhaps tarnished by stories of ‘sick building syndrome’, bad experiences with warm air heating systems from the past or by association with energy-hungry air-conditioning, the merest mention of MVHR elicits extreme reactions. Blogs about Passivhaus often attract bitter comments about ‘suffocating in sealed boxes’ where you ‘can’t even open the windows’ – all of which are completely misguided of course. Sustainability consultants bemoan the energy penalty in running fans 24/7 and warn of the horrors of having to change filters regularly. Meanwhile, the Passivhaus Institute have spent their time perfecting heat recovery ventilation to a level where all of these objections can be quietly and calmly rebuffed. When you appreciate the level of detail that goes into the design of a Passivhaus-certified heat recovery ventilation system, then you begin to understand why there is a level of mistrust in the average UK developer installed system . . .

Airtight construction is, of course, a pre-requisite for heat recovery ventilation and without it, heat recovery ventilation cannot expect to be effective or efficient. As you’d expect, the highest standard of indoor air quality is at the heart of Passivhaus design so well-designed ventilation is critical. We learn that 30m3/hr is the required ventilation rate per person (or around 1.0 m3/hr/m2 assuming German space standards of 30m2 per person) to keep carbon dioxide levels low and remove other pollutants. We learn how higher ventilation rates risk drying out the air and how filtered, dust-free air is more comfortable – think crisp mountain air. We learn the importance of a balanced air passage from the supply point to the extract, so that all parts of dwelling are continually refreshed, but never at more than 0.1 m/s to avoid discomforting draughts. And the more we learn, the more apparent it becomes that reliance on opening windows or ‘stack’ ventilation to achieve the same results is dangerously prone to the vagaries of the weather. However many little blue and red arrows we add to our sections, air will never do as the designer tells it if the outside conditions are not right. So whilst mould growth is not a threat in a Passivhaus, thanks to higher internal surface temperatures, studies have shown that, without heat recovery ventilation, windows have to be opened at regular intervals all day and night to meet air quality standards and avoid a serious energy penalty - not very practical.

The other significant difference is that the heat recovery ventilation system is treated as part of the external envelope in a Passivhaus precisely because you are bringing in cold external air. A great deal of attention is paid to the distance of the heat exchanger from the thermal envelope and the level of insulation on the ductwork as this dramatically affects performance. Using PHPP quickly reveals the loss in efficiency from placing the heat exchanger in the middle of the dwelling as we tend to see in the UK. One great aspect of the BRE course is that we had access to the experts who carry out all the their SAP Appendix Q testing. But even they acknowledge that the more stringent Passivhaus certification, based on actual installed circumstances rather than test rig results, means that non-certified systems have to reduce the Appendix Q efficiency result by 12%! With an emphasis on sealed insulated metal ductwork, jet nozzle diffusers (exploiting the coanda effect to drag air along ceilings), high quality filters, limits on noise breakout and silencers for every room, it feels like comparing golden apples to oranges in relation to the average UK system. We have a lot to learn, not least that you can, of course, open the windows in a Passivhaus – in fact, it’s a requirement for summer venting. The point is, you shouldn’t feel the need to . . .

In a true Passivhaus, the ventilation system is also the heating system and the heating load limit is derived from this concept. With a maximum supply temperature of 52°C to avoid ‘smouldering’ any particles in the air, the specific heat capacity of air at the optimum ventilation rate limits the supply of heat to just 10W/m2, so the fabric has to be designed and orientated to meet this target. For a small terraced house type we recently designed at ECD, as an example, that’s a peak load of 750W, or half the power output of a travel hairdryer, with an energy penalty for the ventilation of just 135 kWh per year.

Another criticism often levelled at Passivhaus is that it is just an energy standard whereas the Code covers a much broader spread of sustainability targets. That is true - Passivhaus compliments Code rather than compete with its broad subject matter. But to avoid getting into a debate about whether some of the other Code categories are sensibly thought out, or indeed save energy or carbon, it is worth remembering that Passivhaus is not only about energy but is also a quality assurance scheme par excellence. Its benefits are well covered in Mark Siddall’s piece for the Greenspec website in far greater depth than I can here but suffice to say the CEPHD course emphasises again and again the role that the Passivhaus designer has in ensuring that the measures are installed as designed, through a number of checks including the submission of photographic evidence to the Certifier along with the PHPP worksheets and design drawings, commissioning certificates and the all-important airtightness test results.

The CEPHD course covers all aspects of the PHPP process including primary energy and summer overheating (far too much to cover in these short blogs) but the final session was perhaps the most feared of all by the room of design consultants – economics. Why is this subject appearing in a design course, you might ask? The answer is that Passivhaus strives to represent a financially viable approach to low energy buildings, rather than say, aiming for a zero heating dwelling or even an autonomous approach. All those housebuilders who recently backed the press statement that zero carbon housing is just not affordable might have some sympathy with this idea. The exam questions will focus on the economic arguments for the Passivhaus approach and might, for example, be based on calculating the energy and fuel bill penalties of downgrading the specification. The complicated bit is that these operational savings are always compared against the alternative of investing the capital in the bank, which introduces the weary CEPHD students to the complexities of compound interest and net present value. Just what you need at the end of an intense 6 days of learning!

At the end of the course, we return to the real world armed with files of notes and the expectation of a three hour, written exam, where even the legibility of our handwriting will be under scrutiny. There’s no going back now. Embracing Passivhaus is a bit like the moment in the movie The Matrix where Neo has to decides to take the redpill over the blue pill – opting to face the physical reality instead of sticking with comfortable delusion. If only you could simply download the CEPHD course to your brain in the same way Neo does with kung fu in the movie - just strike a dramatic pose and announce “I know Passivhaus!” Is there an app for that yet, Wolfgang?

There is a major downside to completing the CEPHD course, besides the scary exam business. My big concern having completed this course is that it makes me realise that every building I have designed, and nearly every detail I have drawn before, has been sub-standard in some way. And working on any future project that isn’t meeting the Passivhaus principles is only going to leave me with a sense of frustration. I’m realistic enough to know that I can’t expect everything that comes out of our office will be to this standard from this day on but when I recently watched Chris Huhne endorsing Passivhaus as the ideal benchmark for all new housing in the UK (blissfully unaware of the real meaning of what he was saying, I suspect), I hoped we were on the cusp of a sea change in the UK construction industry.

Retrofit Project Diary: St. Joan Close - Blog 4

Wed, 03 Nov 2010 15:03:01 +0000

Blog 4: Cost Review and Site Visit, 03/11/10 by Ruairi Kay

Today we had our monthly client and design team meeting for the project, held in addition to our weekly meeting. The main issue on the agenda was project budget! Since our original budget estimate and submission to the Technology Strategy board in last 2009 there has been an increase in the project costs. This is attributed to a number of factors: increase in material costs, i.e. Spacetherm aerogel that has to be imported from the States, changes to the scope of the project and design development, which has lead to a better understanding of the work to be undertaken, but also to an increase in cost. This project is being included within the Decent Homes program already underway by Crawley Homes, and some items, such as kitchens and bathrooms, electrical re-wire and new floor finishes will come out of this separate budget. The rest however has to fit within the finite budget from the Technology Strategy Board. It looks like we are getting back on target now anyway, subject to few value engineering items, which is good as things are progressing rapidly on site.

XPS insulation installed to 400mm below ground level. The new door will sit forward of the existing

On site things are moving along nicely. Inside plastering is now complete, the Spacetherm floor insulation has been laid, second fix electric is almost complete and Envirovent are starting the first fix for the heat recovery ventilation system. Unfortunately air tightness grommets have been missed off the electrical cable penetrations at first floor, so this needs to be rectified. The subcontractor caring out this work had not attended the airtightness workshop held previously and not been briefed when he came on site. This highlights the importance of communicating the airtightness strategy to all operatives on site. Externally the below ground XPS insulation is completed and backfilled, the door opening have been widened (to ensure sufficient clearance after the installation of the thicker framed triple glazed doors) and the main external wall insulation is due to start next Monday. Unfortunately the delivery of the Enersign windows from Germany has been delayed, meaning our target finish date of the second week in December will be pushed back until after Christmas.

MVHR installation on the plant deck in the loft

Retrofit Project Diary: Warnham Road - Blog 1

Mon, 01 Nov 2010 14:39:39 +0000

Blog 1: Introduction, 1/11/10 by Ruairi Kay

33 Warnham road is a 1960’s semi-detached property which has already undergone ‘Decent Homes’ improvements. Works such as window replacement and loft/cavity wall insulation have previously been carried out in a piecemeal fashion and have resulted in condensation and mould growth. The tenant reported less than satisfactory comfort levels, with the building facing extremes of temperature in both the winter and the summer months. The house is built using a timber infill panel system between exposed aggregate cross walls. The infill panels have been updated with uPVC cladding panels. Heating is currently via a gas fired boiler running a wet system of radiators, which replaced the original warm air heating system. In late 1960’s Crawley, a cluster of estates were buillt using this Selleck Nicholls Williams system, mainly formed of semi-detached, short terraces of 3-4 units and 3-storey blocks of flats. This is one of four retrofit schemes ECD Architects are carrying out for Crawley Homes in Crawley, East Sussex - it started on site the October and is due for completion in January 2011.

Front elevation pre retrofit

ECD, Crawley Homes and contractor Wates have worked closely with the residents throughout the design period to ensure that minimal disruption is caused to the returning tenants. The retrofit package will consist of vacuum-insulated-panel (VIP) external wall insulation, top-up loft insulation, replacement triple-glazed windows and entrance door, whole-house heat recovery ventilation and a micro-CHP replacement boiler, supplemented by roof-mounted photovoltaic modules. In addition, 100% LED replacement lighting is proposed to minimise electricity consumption, together with A++ rated appliances and advice to the tenants on how to minimise fuel consumption whilst maintaining adequate comfort conditions.

Retrofit Project Diary: Hasting Road - Blog 1

Mon, 01 Nov 2010 14:22:52 +0000

Blog 1: Introduction, 1/11/10 by Ruairi Kay

22 Hastings Road is a semi-detached property which has already undergone some ‘Decent Homes Standard’ improvements but does not meet the CO₂ emissions demanded of the TSB competition. Works such as window replacement and loft/cavity wall insulation have previously been carried out in a piecemeal fashion and have resulted in condensation and mould growth to the first floor bedrooms within the mansard roof. A standard Cornish Unit design but with a rear cavity wall extension, the ground floor is constructed of solid concrete columns with concrete panel infills to create a void. The first floor is a timber construction mansard roof that accommodates the bathroom and the bedrooms. This is one of four retrofit schemes ECD Architects are carrying out for Crawley Homes in Crawley, East Sussex, started on site the October and is due for completion in January 2011.

Front elevation pre retrofit

ECD, Crawley Homes and contractor Wates have worked closely with the residents throughout the design period to ensure that minimal disruption is caused to the returning tenants. Changes to the property that they will benefit from include external wall insulation to the ground floor and internal insulation to the extension and first floor, 450mm of loft insulation, solar PV, micro-CHP boiler and an aerogel insulated ground floor. A target of low air leakage coupled with a heat recovery ventilation system will ensure a good level of ventilation and indoor air quality. In addition, 100% LED replacement lighting is proposed to minimise electricity consumption, together with A++ rated appliances and advice to the tenants on how to minimise fuel consumption whilst maintaining adequate comfort conditions.

Retrofit Project Diary: St. Joan Close - Blog 3

Tue, 12 Oct 2010 15:02:18 +0100

Blog 3: Airtightness Strategy and on Site Workshop 12/10/10 by Ruairi Kay

Today Ecological Building Systems joined us on site to hold an airtightness workshop with the whole construction team. Airtightness is a very important element of our whole house retrofit strategy. Once we have addressed the issue of heat loss by conduction via insulation to walls, floor, roof and triple glazed windows, the next big contributor to heat loss is via uncontrolled ventilation. The air pressure test result prior to the work commencing was a leaky 9.12 ach/hr @ 50 pa, around current building regulations. We aim to reduce this to 3 or better. Though this is not down to PassivHaus levels of airtightness, this is still an onerous target to achieve in a Retrofit. Once we get down these levels of airtightness, or better hopefully the economics of installing a heat recovery ventilation unit make sense – “build tight, ventilate right”

Starting with the floor, our airtightness strategy is to use the 18mm chipboard aerogel laminate we are applying to the solid ground floor as our air barrier. All joints, junctions and penetrations will be sealed with various Pro Clima products supplied by Ecological Building Systems. Moving to the walls, we will apply a parge coat to the external face of the existing concrete walls prior to application of the EWI. We will be relaying on the existing cast concrete walls to connect the internal floor to the external parge coat at foundation level. The internal faces of the external walls will also be re skimming for good measure. Pro Clima products will be used once again to deal with window junctions and any other breaks in the parge. At roof level we have to rely on the existing first floor plasterboard ceiling, to minimise disruption. Once again all penetrations, junctions and joints will be taped with various Pro Clima products before the application of a new skim coat.

Stephen from Ecological Building Systems showing us how it’s done

Now on to the airtightness workshop! Stephen from Ecological Building Systems was kind enough to join us for an explanation of the use and application of the various Pro Clima products they will be supplying for this project. I was lucky enough to experience a similar workshop at the annual AECB conference a few weeks ago and the skill used to apply the various products really is enlightening. Though the guys on site didn’t quite share my enthusiasm they did seem embrace the whole idea of air tightness and even came up with some useful suggestions. A few issues were identified with our strategy, for example; the Unitape grommets that we are using on the ceiling and then skimming over are not designed to be directly plastered. After some discussion, the site manager suggested we apply the grommets to the attic side of the existing first floor ceiling, thus avoiding compatibility issues with plaster. A similar issue was identified at the junction of the internal walls and first floor ceiling, where we plan to tape with Tescon Profil. In this case we agreed to test a few options and see how the skim plaster stuck to the tape.

After we had gone through all the key issues on this project we ran through the some additional products we are using on our other 3 retrofit projects now underway with the Crawley Homes and Wates Living Spaces. More to follow on these projects under separate blogs.

Excavations to relocate drainage and allow the EWI to run below ground to minimise cold bridging

Passivhaus Training – Windows, Bridges and Air Changes

Tue, 12 Oct 2010 00:00:06 +0100

It’s a common misconception in the UK that achieving the Passivhaus standard is simply a matter of matching a few increasingly familiar yet often misunderstood principles. The usual culprits are “U-values of 0.15 W/m2K, triple-glazed windows, an airtightness of 1.0, heat recovery ventilation . . .” and so on. “Not too difficult . . .” someone only familiar with the Code might think. Well, think again. Above all, the CEPHD course teaches just how much more sophisticated is the interplay of Passivhaus design and its components, and how success lies in the attention to detail that verification via PHPP demands.

In the first part of the course we focussed on the need to balance a dwelling’s energy flows – this is true with any building of course but in a Passivhaus the input energy is limited to solar gains, minimal internal heat gains and top-up heat from the ventilation system (or its equivalent from another heat source). It’s therefore vital that designers have an accurate prediction of the fabric’s heat loss so a more thorough investigation is demanded. One of the complaints about so-called low energy houses is that they haven’t delivered the performance predicted of them - indeed, this design/reality gap was one of the reasons Passivhaus was developed. One reason for this disparity is that the impact of thermal bridging is often grossly underestimated in conventional building models (figures of 30-50% have been suggested as the shortfall) so a good understanding of techniques to avoid them form a key part of the course. Thermal bridging is the phenomenon whereby heat flow out of a building is accelerated by penetration of the fabric, say from structure, party walls or cantilevered balconies. We talk about the Ψ(psi) value indicating the linear thermal bridge loss coefficient and for Passivhaus these have to be shown to be either insignificant (ie less than 0.01 W/mK) or have to be individually added to the heat loss total. SAP 2009 software now allows for linear thermal bridges to be assessed but in practice I suspect this will be hardly used - instead the generic ‘Y’ value will be applied as is current practice. ‘Y’ values add a percentage to the overall area-based heat losses to account for thermal bridging and designers will have to commit to following both Enhanced and Approved Construction Details – one look at these through CEPHD-trained eyes and you can see that they fall well short of Passivhaus standards though. One of the significant differences from SAP is that PHPP measures the external surface area of the thermal envelope, not the internal surfaces as SAP does. At a stroke this overcompensates for the geometric thermal bridges, encouraging the designer to properly account for them as, if designed correctly, they may have negative values which would reduce the calculated fabric heat losses. And accounting for the heat loss from features such as balcony supports makes you really consider the detail from a new perspective. Without this level of consideration to thermal bridge losses, you really aren’t designing to the Passivhaus standard whatever claims for super low external wall U-values you might make.

As the coursework moved on to window design, it underlined that there is a world of difference between specifying ‘triple-glazed windows’ and their PHI-certified equivalents. Windows are a crucial component in a Passivhaus, typically accounting for about 43% of the total heat gains but as much as 50% of the fabric losses. The ambition is to achieve a net positive energy balance ie over the course of a year more heat energy enters the windows than escapes. Real window U-values are derived by factoring in the separate thermal conductivities of the glazed area, the frame area and the Ψ-value impact of the junction between glass and frame. How many UK window manufacturers could readily supply that data breakdown? Continuous warm edge spacers are essential to minimise bridging losses and the overall Uw-value can be no worse than 0.8 W/m²K in order to eliminate cold radiant surfaces and any associated down draughts, referencing back to those all-important thermal comfort criteria. Even then, the effect of the method of installation has to be accounted for, with an additional Ψ-value applied to every window before the final heat loss figure is derived. Contrast this with the basic way fenestration is accounted for in SAP! In a Passivhaus, the windows effectively constitute the building’s primary heating system so great attention has to be paid to the size and orientation of the window as well as the g-value, or solar transmittance, of the glass. Too little south-facing glazing and the shortfall in heat demand cannot be met by the ventilation system. Too much and the building is at risk of overheating. We measured the impact of reveal depths on the solar gains due to their shading on the glazed area - even the impact of dirt on the window is factored in. All this has a profound effect on the way you perceive windows henceforth. For example, it becomes clear that rooflights are hugely problematic and, frankly, best avoided. Think about it - they are always positioned way outside the thermal insulation and are inclined to maximise heat loss on cold days and solar gains in summer! There is one window feature that doesn’t change though, despite what detractors would have you believe – you can, and must, be able to open the windows in a Passivhaus!

Of all the criteria, the one that seems to have most concerned the designers and builders of the first UK Passivhaus projects has been achieving the requisite airtightness of 0.6 n50. That’s measured in internal air volume changes per hour, by the way, not the UK metric which tests the average leakiness of the envelope. Airtight construction is sadly still a bit of a new concept in our industry and the Building Regulation standards in this country are derisory. Passivhaus design seeks very low air leakage for a number of reasons, not least of which is the associated heat loss. Playing with different n50 performance in PHPP shows a dramatic increase in heat demand as more preciously-warmed air leaks through the envelope. Other associated problems from air leakage are less to do with energy losses and more related to fabric damage risk and thermal comfort. The comfort problem is straightforward to understand – greater air leakage equals internal draughts which in turn increases discomfort. German research suggests avoiding air speeds greater than 0.1 m/s reduces the acceptable air temperature by 2Ë�C. The other risk is all about moisture penetration into the fabric, another poorly understood science in UK construction. The narrowest of slits in the air barrier can lead to enormous increases in moisture transfer from the internal air volume. If this moisture then meets a cold surface along the way, you have a serious risk of substantial interstitial condensation, so Passivhaus design takes this very seriously. Low air leakage is tricky to achieve as the CEPHD course visit to one of the exemplar dwellings on the BRE’s Innovation Park pencils revealed. Under depressurisation from a blower door, smoke pencils revealed that external air was pouring in from the most insignificant of gaps, even the entrance door keyhole. Yet, with care, we know it can be done. The Welsh and English Passivhaus pioneers all achieved excellent results, well below the 0.6 n50 threshold and often with the contractor attempting the standard for the first time. But we desperately need more expertise on the techniques involved in the UK – a demonstration in membrane taping at the recent AECB conference by Ecological Building Systems was mesmerising for the skill and tradecraft involved. Time for a new specialism on site?

So accurate accounting for thermal bridging, real window U-values and properly rated airtightness are all essential PHPP inputs and are therefore dealt with thoroughly on the CEPHD course. It is this attention to detail in the fabric design that makes a Passivhaus so much more than the sum of a few headline principles. More in the final part . . .

Retrofit Project Diary: St. Joan Close - Blog 2

Tue, 05 Oct 2010 15:00:28 +0100

Blog 2: Sub-contractor co-ordination meeting 05/10/10 by Dan Jenkins

ECD, Wates and Crawley homes met with Sub-contractors from Solar Technologies (PV), Envirovent (MVHR) and Wattbox (Energy Monitoring) on Friday morning to coordinate ducting and cabling. A meeting was held in the loft space to discuss the spatial requirements of the PV inverter and the MVHR heat exchanger. Guy Henderson from Wates came armed with his coloured marker pens to draw the cable and duct run locations on the walls. In the end, the coordination discussions went so smoothly that the pens weren’t required. Sorry Guy..

Retrofit Project Diary: St. Joan Close - Blog 1

Wed, 29 Sep 2010 14:44:06 +0100

Blog 1: Introduction, 29/09/10 by Dan Jenkins

10 St. Joan Close, one of four retrofit schemes ECD Architects are carrying out for Crawley Homes in Crawley, East Sussex, started on site the 6th September. Due for completion at the beginning of December, the existing residents are looking forward to celebrating Christmas in their ‘new’ energy efficient home.
ECD, Crawley Homes and contractor Wates have worked closely with the residents throughout the design period to ensure that minimal disruption is caused to the returning tenants. Changes to the property that they will benefit from include a EWI thermal jacket with 400mm of loft insulation, solar PV, micro CHP boiler and an aerogel insulated ground floor. A target of low air leakage coupled with a heat recovery ventilation system will ensure a good level of ventilation and indoor air quality.

Front elevation pre retrofit

Passivhaus Design - ECD reports from the BRE's inaugural CEPH Designer course

Mon, 13 Sep 2010 15:24:09 +0100

I think my A-level Applied Maths teacher of some 25 years ago would have been pleased with me today, as would my A-level Physics teacher. I suspect some of my tutors from the combined architecture and engineering degree at Bath University back in the late ‘80’s would have felt some measure of satisfaction too. Because today was probably the first day since qualifying as an architect that I really applied my maths and physics knowledge, handwritten equation by handwritten equation, to the design of a building. And it was a surprisingly satisfying experience . . .

Along with 24 other eager guinea pigs, I am currently one third of the way through the BRE’s inaugural Certified European Passivhaus Designer course in a classroom at their Garston site getting to grips with the delights of psi values and the idiosyncracies of PHPP. We are a mixed group of architects, technologists and engineers from across the UK and Europe but all sharing a keen interest, and in most cases a passion, for the gold standard in low energy design. It’s a curious beast, a Passivhaus . . . Not really passive because it embraces mechanical systems to achieve its staggering efficiencies - they’re not even houses a lot of the time. At the cutting edge of construction practice yet measured with a humble Excel spreadsheet. It has its own language of metrics and terminology, in many ways familiar to the mainstream jargon of TERs and W/m2K but always in a slightly parallel German universe based on TFA’s and W/m2 instead. And whilst you will always recognise a Passivhaus designer because they can only ever tell you the size of their building “excluding the partitions, plant and stairs” or because they talk in air changes per hour not “cubic thingy’s per thingy per thingy”, it is also a completely open source standard and utterly removed from any kind of exclusivity – contrast that with the mysteries of the zero carbon definition if you will?

Passivhaus design is on the one hand totally unprescriptive but on the other rigidly unforgiving. No two Passivhaus buildings have to look alike, but miss those verification criteria and you’re not part of the club. Much like the PHPP tool (possibly the most loved spreadsheet in the construction industry?), Passivhaus buildings are often simple and unassuming on the outside but you know there’s some very careful clever science going on behind the scenes. And best of all, it works! Twenty years of monitoring have shown a close correlation between design performance and the average actual measured performance across wide samples of housing.

At the beginning of this blog I referred to us as guinea pigs, as this is the first CEPHD course in England, but I think we owe a debt of gratitude to the pioneers who went through the first ‘English-language’ course a year or so ago in Glasgow. I have heard many stories from the UK’s Passivhaus vanguard of late nights struggling to read German-subtitled slides whilst being lectured on complex concepts of energy flows in broken English. Our course tutors, Gavin, Rob and Kym, went through that experience and as a result have burnt a considerable amount of candle translating the maths and terminology into recognisable English. Even then some things slip through – anyone know what a “roof innershell flap tile” is?

So after two days, we have been given an introduction to the breadth of Passivhaus design exemplars out there and delved into the myriad of input fields in the PHPP spreadsheet. We have hand calculated U-values and approximated psi values. We have learnt the importance of balancing our energy flows and the critical role surface area to volume ratios play in achieving an energy efficient design. Passivhaus design has been described before as accountancy. Account for all the heat losses, ie through the walls, ceilings and floor; through the thermal bridges; through the windows; through the ventilation system and through residual air leakage - then balance them against all the gains: solar incidence and internal heat gains. Whatever is left has to be low enough to deliver via a ventilation system without affecting ventilation rates and efficiencies. Simple really! Except you have to evaluate them in the context of real world climate data over the changing seasons, whilst considering whether your layouts and construction methods are economic and buildable.

Tomorrow, we tackle window and heat recovery ventilation design. One of the interesting aspects of Passivhaus design for architects in particular is that it makes you take back some control over the many design aspects we have given away over the years. Who needs to engineer a complex heating system when my entire building has the peak heating load of a hand-dryer even when its -10°C outside? The other delightful aspect is that it’s all based on thermal comfort standards – air temperature, even and just right; radiant surface temperatures, comfortably less than 4°K difference; internal air speeds, imperceptible; and humidity, not too high or not too low. It’s about human enjoyment of the building as much as it is about tackling our energy crisis.

I often hear from Passivhaus detractors that “the Code and ‘zero carbon’ are the only game in town, you know. Why bother with Passivhaus?” But from what I have seen so far, the circus surrounding the zero carbon definition seems like exactly that - a game about carbon offsetting. Meanwhile, the serious business of reducing the energy efficiency of our buildings is about quietly embracing Passivhaus. More next week.

Presentation on Improving Energy Efficiency in Flatted Dwellings by James Traynor (ECD) at NEA Fuel Poverty Forum.

Mon, 28 Jun 2010 17:14:51 +0100

James presented the results of the research recently carried out for Westminster City Council and Dolphin Square Foundation into Energy Efficiency in Private Flatted Dwellings. The overall objectives of the research were to reduce CO2 emissions and to reduce fuel poverty. The more specific aims of the study were to explore the legal, financial, social and practical obstacles to implementing energy efficiency measures in the private residential sector. UK householders are currently responsible for 28% of UK CO2 emissions and in London homes are currently responsible of 38% of all the city’s CO2 emissions.

The Government has identified housing as a key sector to reduce CO2 emissions and reach climate change reduction targets. The UK Low Carbon Transition Plan (2009) requires CO2 emissions (from heating) in the domestic sector to fall from 13% to virtually zero by 2050. It identifies a range measures to support improvements to energy efficiency including: Smart metering; finance options; community scale action; self-help support, etc, to support the ‘Great British Refurb’. Announced in February 2009 this consultation document calls for all homes to have undergone a ‘Whole House’ refurbishment of energy saving measures by 2030. That includes a comprehensive package of measures to address CO2 emissions.

In Westminster there are currently a total of 86,500 private sector homes with an average SAP rating of 58 in 2001. However one of the key challenges in Westminster to addressing this issue is the nature and location of the properties involved as the makeup of the housing stock varies considerably from the national average. Approximately 90% of dwellings are flats rather than houses (nationally the converse is true in approximate terms). Westminster contains a large private rented sector – some three times the national average and contains a much higher proportion of stock that is listed or in a conservation area.

Furthermore the stock is older than the national average and has a disproportionate number of buildings with solid walls and a significant number of domestic dwellings with flat roofs. The Rugg Review completed in 2008 indentifies the state of the current UK private housing rental sector and in particular the challenges facing upgrade of this stock including: Poor/ unregulated management; ignorance of statutory requirements; low standards; older housing stock; higher yields on poor quality housing and short-term tenures. All of these issues need to be addressed in any serious attempt to introduce energy efficiency measures generally and in Westminster in particular.

A common (but not universal) feature of landlord and tenant law in England and Wales is that long leases contain provision for the respective obligations and rights of the freeholder and long leaseholder in respect of repair and maintenance but are silent on the matter of improvements. In order to carry out works to common parts of the building it is necessary for all leaseholders and the freeholder to agree to carry out these works and for the leaseholders to agree to fund the works plus future maintenance requirements.

All of the above present challenges to the improvement of the energy efficiency of the housing stock and Westminster City Council residents have as a result received a limited amount of nationally and locally available energy efficiency resources for retro-fitting the private sector housing stock. Given the wide ranging and complex nature of the research required, including the process of resident involvement and selection of suitable properties it was clear that a systematic and methodical approach would be required.

Working closely with the client the project team identified the following processes by which this research should be carried out:
1. To identify six flatted buildings
2. To liaise with freeholders to secure commitment to explore improvement options.
3. Contact occupiers via an introductory letter explaining the project and service on offer.
4. Provide participating leaseholders with personalised advice about the potential energy efficiency improvements within their individual flats.
5. Provide verbal and written guidance to the freeholder and leaseholder for each building regarding the process for consulting their respective lawyers regarding alterations to their individual leases.
6. Provide leaseholder with written and verbal guidance on how to obtain financial assistance towards the building works and any associated legal costs.

Having prepared detailed assessments for each property with proposals for improvements and collated legal, financial and technical data, ECD then met with leaseholders and freeholders to discuss options for uptake. The Phase 2 work will involve the implementation of some of proposed phase 1 works in one of the selected properties to demonstrate the challenges to improved energy efficiency and how these might be overcome.

The results of this wide-ranging research will be used by Westminster City Council to lobby central Government for targeted assistance to deal with these complex issues to address the barriers to wide scale uptake of energy efficiency measures in private sector flatted dwellings. This approach will ultimately deal with both fuel poverty and carbon reduction targets whilst addressing both the planning issues associated with historic buildings and legal issues associated with flatted buildings.

To see a copy of this document, please click here.

ECD's Mark Elton on Ecobuild

Fri, 05 Mar 2010 10:48:45 +0000

I can scarcely believe it but Ecobuild has somehow managed to get even bigger in 2010. For those who remember its modest beginnings barely five years ago when there could have been no more than a few dozen exhibitors in the lobby at the QEII conference centre, its exponential growth is testament to the rise in interest in all things ‘sustainable’ in the ensuing years – or more likely to the ability of the mainstream construction industry to rebrand itself in a greener shade.

It is now utterly implausible to expect to visit for a day to take in a seminar or two, pick up some interesting product literature, catch a debate in the main arena and return home feeling that you had the event covered. The choice is overwhelming and the feeling you are left with is one of having only scraped the surface. There is something about the quirky footprint of Earls Court though that gives the event some of its character, coupled with the proximity of good tube links and local hostelries of course, and you wonder how it will fare next year in the regimented corporate order of ExCel, where presumably it aims to get even bigger? Remember Think anyone?

Despite its scale though, it is still remarkable how many people you can bump into when crossing between events and thanks to Twitter, it is now even possible to co-ordinate your congregations. The fact that it draws so many visitors and speakers from all over the country makes it a unique networking opportunity not to be missed. Its also interesting how different perceptions of the exhibition can be formed depending on the observer – some people bemoaned the fact that it was all solar products this year whilst another could only see external insulation solutions wherever they went! All of which is really a precursor as to why it is so hard to find new products to blog about – you can only ever hope to capture a snapshot of what is available.

My two interests at Ecobuild this year are Passivhaus and retrofit so to narrow my search I stuck to these themes in my selections. I was also keen to avoid the big companies so I was delighted to come across Passive Windows, a company based in Orpington, Kent manufacturing bespoke, FSC-certified timber windows with a typical Uw of 0.8 W/m²K, including a unique ‘open out’ range in line with UK preferences.

Although not yet Passivhaus Institute accredited, these windows offer exceptional thermal performance through the combination of a thermally broken timber frame, via a polyurethane core, and low-e, argon-filled triple glazing with warm edge spacers. Most importantly though, they are fabricated within the M25 meaning they should be less prone to lead-in time and cost issues than their continentally shipped counterparts. Additionally, they will match the same high thermal performance in their entrance and sliding/folding door ranges. The unusual ‘parallel open out’ window also seems quite ingenious where security might be a concern when summer ventilating.

On the fabric side, I got my first chance to see the Energyflo dynamic cell product up close, having read about it on this website previously, among other sources.

The company behind this product, ECT, has developed and patented a range of building insulation products that aim to transform the building envelope into both a heat exchanger and source of fresh ventilation air. It comprises a perforated and hollow polystyrene cell, a bit like an ICF block, which sits in a cavity or between studs to form in effect an insulated chimney through which air is continuously drawn via a low watt fan at the top of the wall. The idea is that any heat lost into the cavity is returned to the building via positive input ventilation or even heat recovery ventilation. The attractive claim of achieving U-values of around 0.1W/m²K or less with an insulation thickness of only 140mm arouses both interest and suspicion but Energflo have had the performance verified by the National Physics Laboratory. The proof is in the pudding however and it will be interesting to see some real data from the first installations to back up the argument.

There is a lot to interest the retrofiterati at Ecobuild for this year including a number of new products to suit internal wall insulation situations such as Knauf’s new Ecostud/Earthwool combo or pro Clima’s Calsitherm board. Many people argue that we should leave difficult to treat properties that need IWI until we have completed the swathe of EWI installations needed but when presented with the opportunity to retrofit stock that has architectural or heritage value it is great to know that there are solutions out there. One that caught my eye though was Edenbloc rigid insulation from Second Nature.

I remember enquiring about this product nearly four years ago at an AECB conference and was surprised to get a phone call earlier this year announcing that it was now available. Launched at Ecobuild, it is a rigid, paper-backed insulation made from wool and recycled waste (mainly from the carpet industry) that achieves a thermal conductivity of 0.035 W/mK – impressive for a natural insulation. It has a very low carbon footprint and locks up twice its weight in CO². It can be delivered in sizes up to 350mm thick, although it would be advisable to layer up with smaller thicknesses to avoid thermal bypass if performance at this level is sought. It is supplied with a vapour control layer and is pinned to the existing wall with battens – Pro Clima-type membranes can be substituted where you are after fully breathable construction. At £82 for a pack covering 2m² at 100mm thickness it’s not as expensive as first imagined.

Heat recovery ventilation is often disruptive to retrofit so it was great to discover the energiVent® Impact single room heat recovery unit for use in commercial application such as pubs and restaurants.

Now that these sorts of building are no longer filled with smoke there is a reduced need to ventilate so highly meaning that there are lots of overpowered extract fans sitting in walls across the country. This unit is designed to be retrofitted into the same space as the original fans but can recover around 70% of the heat from the outgoing air to pre-warm a return fresh air supply. As with all their products, Envirovent really consider the practicalities of durability, maintenance and life-cycle, removing the need for any parts to go to landfill – which is nice.

And finally, I have to give a plug (no pun intended) to our friends at Wattbox with whom we have achieved a degree of success in the Technology Strategy Board’s Retrofit for the Future competition. The Wattbox is a new heating controller designed to reduce energy consumption in residential buildings – it controls both central and water heating, reducing consumption by automatically monitoring and learning occupant behaviour and preferences. It has been under test and development for 4 years but is now ready for the wider-scale field trials that the TSB competition is funding. As well as providing a whole house control solution, it can also provide a whole house data acquisition solution, invaluable for getting retrofit feedback. It has a really simple interface with only two switches to control for internal temperature and one other for more hot water. No need to set programmers and such like - it learns all that for you.

The trials, which were carried out on a domestic microCHP unit suggested that the Wattbox could save around 12-15% energy in the winter months and 30% of hot water energy use in the summer months. Every time we have asked Wattbox if their unit can control a new appliance or measure a new set of data the response has been positive and we really hope to play a part in helping them get established.

I will finish with a quick mention for an organisation present for the first time at Ecobuild this year Passivhaus Buildings, based on the AECB stand. Passivhaus Buildings is the successor to AECB Carbonlite and aims to be a centre of excellence for information, knowledge and skills about low energy, low carbon buildings. It intends to develop accreditation schemes for individuals, organisations, products and services delivering low energy or passivhaus developments helping to generate flagship schemes. Find out more at www.passivhausbuildings.org.

ECD Project Wins the Inside Housing Low Energy Social Housing Project of the Year Awards 2009

Mon, 18 Jan 2010 14:35:17 +0000

ECD Court Farm Road ‘Retrofit & Replicate’ has been awarded winner of the Inside Housing magazine’s Low Energy Social Housing Project of the Year Award 2009. The Inside Housing Sustainable Housing Awards celebrate ‘the projects and organisations at the forefront of housing sustainability best practice.’

Announced Friday, 23 October at the London Hilton Hotel, the award was received by client, Hyde Housing Association, and the ceremony was attended by members of the design team (ECD Architects, Keegans and Mears).

Retrofit & Replicate involved the refurbishment of a 3-bedroom, non-descript, brick terrace house built in the 1930s with a flat roofed rear extension added in the 1980s. As an average family home, typical of Hyde Housing Association’s stock, the house underlines the purpose of the project to identify replicable solutions for reducing CO² which can be used in everyday homes right across the country.

The new residents were selected on their willingness to be involved in an ongoing comprehensive monitoring to determine energy consumption. Provided with an understanding of how best to maximise the energy savings in their new home, the property continues to be monitored for the level of CO² emissions and ultimately the cost effectiveness of the different technologies employed throughout the property.

ECD Winner NHIC Awards

Tue, 05 Jan 2010 09:44:29 +0000

ECD Court Farm Road ‘Retrofit & Replicate’ has been awarded winner of two awards at the National Home Improvement Council Awards 2009:

• The Big Green Home Award
• The George Plucknett Award

The Big Green Home Award was presented to the project which demonstrated the widest range of energy efficiency products, measures and microgeneration technologies to be retro fitted, maximising cost/payback and CO² savings. Judges comments reviewing the ECD submission stated:

The judges were impressed by the range of solutions the products utilised, which combined to deliver a predicted 85% reduction in the house energy consumption and a potential £600 saving on the annual energy bills. It is a great example of what can be applied to the social housing sector, addressing fuel poverty and CO² emmissions.

The George Plucknett Award is presented to the organization which has completed a project htat most closely fulfils the objectives of the NHIC. The winning entry is chosen from the winners and finalists from all categories of the NHIC Awards and so represents an outstanding level of achievement. Judges comments in nominating Court Farm Road stated:

Winner of Category 7 [Big Green Home Award], another facet of this project is to establish what it is like to live in an energy efficient home. As a result ‘post occupancy’ interviews are being conducted to assess residents’ to the eco-measrues employed and the impact these measures are having on comfort and satisfaction at Court Farm Road.

The NHIC represents companies and organisations that work in the home improvement sector and they earnestly believe in higher standards of materials and workmanship, backed up with codes of practice, guarantees and warranties.