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

Tuesday 8 February 2011

Weather relents and progress regained!

So, once the weather relented in January we were at last able to make some real progress on site. Firstly the external insulation was fitted between the rafters to allow the roofing to continue. Fiddly this with the extended rafter foot needing to be accommodated within the insulation zone, but essential to maintain progress.

Then window fitting could proceed at last, and some experts from the supplier soon had these in place. Remarkably this seems to transform the site and it begins to take visual shape. Extended protection has been applied to protect the PPC finish, and the extended sills look exposed awaiting the insulation placement.

Insulation placement has been a problem as both air and surface temperatures need to be above 5 degrees, so maybe January wasn't the best time to try and do this, but things are warming up and so hopefully we'll soon be wrapped up nice and warm.

Fortunately it is not on the critical path, so Bramall have been busy internally, first fixing mechanical and electrical, including the MVHR ducts.

Further work has been going on as well on completing the various membranes and tapes in preparation for an initial, pre-plaster air leakage test. Although the plaster is our actual air leakage membrane, it is felt worth testing before plaster to see if there are any unforeseen areas that may need attention. Bramall have purchased their own 'hovercraft' as it is known and we anxiously await the first test results.

The photo here shows the air tightness tapes around the window and door frames before sealing to the walls, and the DAS tape at the junction of the wall to the floor. All of these get plastered in so as to link to the air tight plaster membrane.

And I can't sign off without congratulating the Bramall site team on the quality of the catering at site meetings which is much improved since my first blogged comment!
Ahh, the power of the internet!!

Chris Parsons
Parsons + Whittley Architects.
Feb 2011