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Passivhaus Pass

Posted: October 11, 2013

There is no ‘can do better’ assessment for leading window industry innovators Sidey Limited on their latest achievement as a partner in the 14 unit Passivhaus development at Ditchingham in Norfolk.   The scheme is the latest to be formally Passivhaus Certified and the Perth based company is delighted to have played a major part in it. 

On the surface the deliberately simple Passivhaus standard to build houses which have excellent thermal performance, exceptional air tightness, and contain a mechanical ventilation system should not prove to be over challenging; the reality though is that there are so many hidden challenges to overcome to enable this to be achieved, that working on this kind of development is anything but a simple process.  It is the belief of Passivhaus pioneers Bo Adamson and Wolfgang Feist that to build with these principles in mind will achieve accommodation standards which far exceed anything that has gone before and will future proof a development against the on-going process of climate change, and address the need to reduce reliance of fossil fuels thereby cutting CO2 emissions.

Sustainable building practice in its truest sense; for the partners on the second Passivhaus affordable housing development for Hastoe Housing Association it was a real chance to show their skills as designers of very bespoke, highly technical and innovative solutions.

Mike Stevenson Development Director for Sidey Limited takes up the story. “ Like thousands of other companies over the last 30 years we have supplied tens of thousands of windows into social housing;  as the years have gone on specifications have become ever tighter and more demanding, and it is no longer enough to just supply and install the window.  It is how the windows interact with the rest of the structure to contribute to the performance of the whole building envelope that is critical.  The passivhaus scheme at Ditchingham was the ultimate test and proof positive that the requirement to formally integrate windows and doors into the structure of this kind of development can be met.  We are delighted to have played such a significant part”.

Most challenging was how to develop and provide a structural cavity closer which would bridge the 300mm gap and still support the weight of windows which were triple glazed.  How to provide a measurable air-tightness method that was fully integrated into the window installation, and how to protect all of these elements during a demanding build process were among the other challenges facing Sidey.   All of this was further complicated by a secondary  need to ensure that the products met the requirement for building lifetime homes and secured by design, as well as offering some aesthetic appeal for the residents who would be moving upon completion.

On the surface a seemingly unworkable mixture of demands and requirements which meant that early involvement with the design and specification process was essential.

Mike continues “to meet the many and varied requirements of the brief it was essential that we had early involvement with the designers and constructors.  All parties recognised that we could not simply turn up later with a standard window and expect that it would contribute anything to the very demanding needs of this particular site.  Our first task was to design a structural cavity closer to bridge the 300mm cavity and support the weight of the windows which needed to be triple glazed. 

‘On the surface a seemingly unworkable mixture of demands and requirements’

We were able to do this so successfully that the windows we supplied were not compromised in any way in terms of style or size, meaning the future residents would have a pleasing window design.  We were able to use our own preferred and already tested airtightness membranes to ensure that there was no air leakage, and installation by our trained operatives meant that we could be confident that everything would perform exactly as it was designed do once installation was complete.”

“ The actual windows and doors themselves had their own challenges; a requirement for triple glazing,  a whole window U value of 0.8, the need to be secured by design compliant, and a requirement to be fit for purpose as products installed into ‘lifetime homes’.  Add in the requirement for the doors and sidelights to be building regulation Part K compliant in terms of barrier loading, and you can imagine how much effort was required”.

‘Installation by our trained operatives meant that we could confident that everything would perform exactly as it was designed to do’

“We chose our Solartherm Plus ® windows and composite doors for the site including a coloured frame to match the overall scheme design.  We were also able to support the overall site works by factory applying our patented Scratchguard ® re-cyclable glass coating which meant that the extremely high specification sealed units were not subject to damage on site, and would not therefore be the cause of any unforeseen costs to the client.  In fact it was refreshing for us as a company with a wholly UK based supply chain to be able to get involved in a scheme of this nature  knowing that so much of our involvement as a company and the products we supplied are genuinely contributors to sustainable development when judged against all the accepted criteria”.

The first completion of this type of construction was completed in 1991 and the Passivhaus building philosophy is claimed to be the fastest growing energy performance standard in the world. The latest development for Hastoe Housing at Ditchingham and the contribution by all the supply chain partners to make it happen,  would suggest that there is no reason why this kind of development should not continue to grow in popularity in the years to come.