Building My Net Zero Energy Home: Foundation Details for Airtight Design

Reader Contribution by Staff


Finish foundation. Notice that the top surface of the wall
has been leveled and hard troweled so it is smooth. This helps create a tighter
fit between the sill plate and the concrete to reduce infiltration and
exfiltration – air movement in and out of a house.  Be sure to install sill seal foam beneath the
sill plate for a very tight fit.

The photo below shows a close up of the top of the wall.
Notice the two J bolts – one for the exterior 2 x 4 wall, the other for the
interior 2 x 4 wall. As I noted in an earlier blog, I decided to build double 2
x 4 walls because it was considerably cheaper than ICFs and structural
insulated panels. I am also very familiar with this technique, having used it
to energy retrofit my 2,400 square-foot classroom building.  I would have liked to have used straw bales,
but they are strictly forbidden in my county thanks to the fire commissioner’s

Contributing editorDan Chirasis a renewable energy and green homes expert who has spent a lifetime learning life’s lessons, which he shares in his popular blog,Dan Chiras on Loving Life. He’s the founder and director of The Evergreen Institute and president of Sustainable Systems Design. Contact him by visitinghis websiteor finding him on.

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