Friday, 18 February 2011

Initial Air Testing

Visited site today to witness the first air testing of the properties. The air tightness strategy is not yet complete, as the main air barrier is the wet plaster, but as we are getting close, and all of the membranes are fitted, or nearly fitted, we thought it was worth testing the units to see where any unforeseen problems might be occuring.

Dominic had skilfully mounted the Wincon unit in a panel and fixed it into the door opening, and wound the pressure up to 50 Pascals to see what was giving. Initial testing just by hand highlighted some problem points in the ceiling Intello membrane, and a few leakages around Internorm's factory fitted Illbruck tape but on the whole nothing really surprising. Sealing of a few service penetrations was happening whilst the test was underway and then a closer investigation with a smoke pen highlighted some more suspect areas.

The boffins will work out the actual air leakage on a rough and ready measure over the next few days, but at least we have started to find the weak spots in the design/construction before we plaster.

The other exciting development was to see the insulation being fixed in earnest. This has been delayed for a couple of reasons but now that it is underway the buildings start to take on a bit of texture as the windows settle into the cosy covering of 285mm of Springvale's Platinum EPS. With a Lambda of 0.030, this, coupled with the rest of the wall construction, will give a U value of 0.080, making it the most thermally effective wall we have ever undertaken.

We also showed a journalist from Greenbuild magazine around this afternoon, and talked to her at some length, (my friends down the pub already call me a passivhaus bore!), about the project, the challenges we have faced, and the issues the scheme has presented, but on the whole, still a positive experience and a sense of expectation is gathering as more and more of the final elements fall into place.

Chris Parsons

Parsons + Whittley Architects

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