Sunday, April 18, 2010

Air sealing the exterior shell

Hello again,
Another good week. We finished air sealing the exterior shell, tested it for air leaks, installed the windows and got on half the second roof on and covered it for a pending rain. On Friday and Saturday more than 140 people, CLAM members and building professionals from all over the Bay Area, came out for the "See the Guts" Tour to see how the Passive House is put together from the ground up, focusing on the air sealing of the exterior shell.
See you next week..............Terry

Our first blower door test with no windows cut in revealed our "D" ring was too big and we got fluctuating read outs. For those who do not know what that means: a "D" ring is used in super air tight tests. I called up the manufacturer of the blower door company and they said "Holy ~*^- ! you guys are in "E" ring territory, we don't see that very often."

Here Bill is putting tape over our D ring in an attempt to make it smaller so we might get the LOW flash to stop going off. It worked and we got .11 and .12 CFM readings (not accurate but revealing). Again, for those who do not know what that means: you could not find a hole big enough to let a fly egg pass through.

After the first blower door test we cut out the plywood sidewall in preparation of the windows. We used Serious Windows with an R- value of 7 and equally as important, Serious windows are very air tight. here Jorge, Sebastian and Bill are tilting the window into a wet bed of caulk.

I did a second blower door test after all the windows were installed to see how much they leaked.The new test numbers showed a negligible difference, verifying air tight windows and installation. Note: I blue tape sealed the blower door shroud all around the jamb and tightened a bungee cord around the fan shroud to assure no leakage in the assembly. I also ordered the E ring for the next test.

Ready for next roof. Shell exterior air sealing is done.

Next roof- this time with two foot overhangs.

3 1/2" polyisocyanurate (rigid foam) in between the 2x4 sleepers/ overhangs.

James Bill of ZIA (zero impact architecture)and the Passive House architect for Blue2, explaining the coolness of the Passive House on the "See the Guts" Tour.

Charles of Mr Insulation showing a demonstration/sample wall section of insulation at the tour. We screwed up two sheets of ply, drilled three 1 1/2" holes and Charles blew in dense pack cellulose behind the plywood. We then pulled the ply off to reveal these packed cavities. We will be using cellulose for all the interior insulation.

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