A Slick Transition from Foundation Insulation to Wall Sheathing

May 3, 2018

 

Outside insulation is an efficient way to keep heat in. The devil is in the details like this one

 

Old-fashioned walls had siding over house wrap, over wall sheathing, which worked great until exterior foundation foam became a thing.

R-15 foundation insulation is required in cold climates, like Minneapolis, and the best way to do it is to the outside. This means about 3 inches of insulation.

You could add a wide flashing to span the foam, but OA Design Build has another way to do it.

 

Step by step:

  • They begin with waterproofing on the outside of the foundation all the way to the capillary break on top.
  • Next comes the insulation.
  • Cantilevering the framing over the edge of the foundation about ½ in., leaves just enough space above for ZIP R-12 sheathing to flush out with the face of the foam.
  • The joint is then taped against air leaks.
  • The local building department requires a plastic slip sheet below grade, to protect against frost heave.
  • They also require a protective cover, like coil stock, above grade to protect the foundation insulation.

Now they can add a rain screen and siding for a neat transition that keeps the heat where it belongs.

 

—Michael Anschel owns Otogawa-Anschel Design+Build in Minneapolis, Minnesota

 

Detail and Download

Foundation to Zip Transition.jpg

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