Wednesday, July 11, 2012

Walls like a sandwich, Insulation Information

The wall construction of a passive house is one thing that makes it very distinct from a standard building.  Our architect Jamie Wolf told us when Passive House "geeks" get together, their line is "What are your walls?" meaning what are the materials and construction you use in the Passive Houses you build. In my last blog entry, I described the first blower door smoke test to check for air leakage in the outer wall structure. We have come to the next step in wall construction, the insulation.  Jamie describes his walls as a "Sandwich Wall".  Basically, it is a double stud wall with several layers of insulation. Outside to in, an outer stud wall with dense pack cellulose blown in between the wall studs retained by a mesh batting (the bread). 

Dense pack cellulose being blown in between the wall studs
Next is a 4" thick layer of EPS, then a 1" layer of Polyisocyanurate (Meat and cheese).

Three layers out of the four done

Finished off with an interior stud wall with dense pack cellulose blown in between the studs and the interior wall board (bread again).  Insulating and appetizing. Great care is taken to eliminate air leakage and thermal bridging which is heat loss through conduction.

I have been a little remiss about blogging in real time. A lot of progress has been made at the Green Box.  I'll catch up in the next couple of entries.

Currently, the interior stud wall is partially constructed but will not be closed in with wall board until all the electrical, plumbing, ventilation, and heating/cooling lines are finished being installed in all of the interior walls so they can all be closed up together.  In addition, the windows are in, the roof shingles are on, and the screen porch and front porch are in the works.  More details and photos soon to come.

I love our windows
In other news, our green box is an official participant in the CT Zero Energy Challenge for 2012. Check out our entry and the competition at are entered as WolfWorks - Harwinton,CT.

1 comment:

  1. Hey Paul and Diane! So psyched to find your blog! We too have a plot in Cornwall and have been researching passive solar home designs to build there. Due to the lack of sunlight in CT, we're leaning more towards building a full passive house instead. My internet research lead me to your passive house in Harwinton--Congratulations! I'm eager to learn from your experience and to someday soon visit your beautiful new home:) Rachel (Marina's mom)