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Community and Q&A

Sill plate and sheathing interface

ckfk | Posted in Green Building Techniques on

I would like to inset the Zip R12 sheathing on the poured concrete stem wall.  I would extend the Sill Gasket or interior floor vapor barrier to the stem wall exterior and then apply liquid flashing over the Zip sheathing to stem wall interface.  Is this OK to do?  I have searched for example of this detail and haven’t found any.  I have only seen the sheathing overlap the exterior stem wall.   What potential problems are there with this approach?  I’m in climate zone 6.

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  1. GBA Editor
    Martin Holladay | | #1

    Q. "What potential problems are there with this approach?"

    A. Concrete foundations are rarely perfect. Instead of following a perfect chalk line, a foundation can wiggle in and out by 3/4 inch or so. If you follow your plan, make sure that your sheathing is proud of your foundation. You certainly don't want the foundation to be proud of the siding, since a protruding concrete lip can catch rain water.

  2. ckfk | | #2

    Excellent. Thanks Martin.

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