I stopped by the high performance home site today and listened to the subcontractors in the attic above me murmuring about how it was such a pain to get anything done with the membrane already installed on the ceiling below. I chuckled.
As high performance home builders, paying attention to energy details is important to us, and unless you are committed to the process it would be very easy to cut corners in the name of getting things done quickly. Sometimes a few more hours of labor are worth it in the long run. Plus, I’m not the one in the attic trying to get the work done. I chuckle.
I mentioned in a previous post that we use the Intello Plus membrane on the interior surfaces of this high performance home. We install it on the ceiling before framing interior walls when possible. If the attic has enough room to walk around in then it’s doable, but if it’s a low pitch roof it’s not. Electricians and plumbers need to have working space to be able to run wires and glue pipes together.
The exterior walls are another story. The membrane cannot be installed before any interior framing is completed because the electricians would not be able to run wires in the wall. It’s a twelve-inch-deep wall, and even though some of the electricians are smaller in size and could fit in the wall cavity, they would not be able to get much work done no matter how many energy drinks they consume before coffee break.
To overcome this challenge, we cut strips of the Intello membrane and tack them in place on the exterior at each location where an interior wall will connect. After the electricians have completed the work of rough wiring, we install the membrane on the remainder of the wall and tape all the joints. To date, we have not discovered another approach that is more practical while also creating a thorough air seal. The electricians appreciate not being stuffed into the wall cavity as well. Everyone is happier and the house is more energy efficient. Very important.
Here are some more pictures of the project: