Tuesday, 23 April 2013


Monday was the day ... airtightness test day.

Readers of this blog will know we've worked since November to make our new home as airtight as possible. We don't want expensive heat leaking away! A score of 3 is considered good and the passivhaus 'Gold Standard' is 0.6.

So, 8:00am Monday and William sets up his contraption in the door, links up his laptop, clipboard ready. This image gives a 'Close Encounters' impression. Actually, it seemed a bit more like the kind of invention that Prof would have come up with in 'Back the future'. The contraption has a fan that expels air from the building, sucking air out and from this he could read how much resistance was being created. First we noted that the exposed airtight membrane was being sucked inwards, creating padded cell effects around the wall. Then, we began too gasp for breath and the skin on our faces grew taut giving us a wild-eyed, cadaverous appearance. Actually, these latter points didn't occur at all.

I did hear a rushing noise and found that one of the skylight Velux window ventilators had been pulled open and air was rushing in. Easily closed.

When the window was closed, there was still a little air ingress from around the Velux window seals. This was possibly caused by a little dirt.

But it didn't matter.... Our score was a brilliant 1.3! Even with dodgy window seals!

The score should rise as the plastering will give another layer within the already airtight membrane.

The road to airtightness has been an arduous and worrying one. But we made it!

Great work to everyone who helped with the membrane and various tapes used to achieve airtightness. Special thanks to Steve who discovered Siga .....  and to our Siga products trainer Declan.

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