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Rigid foam wall detail question

quantumgirl | Posted in General Questions on

When putting two layers of 3/4” rigid foam between housewrap and siding (plus rain screen between foam and siding) do I need to put some kind of tape or metal flashing on the bottom edge of the foam to keep critters from eating it?

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  1. Russell Miller | | #1

    Yes, some painted aluminum, bent on brake will do the trick. I like to come up the wall 12" over top of the foam and tape it back to the foam.

    Think of a 1 1/2" x 12 inch "L"

    1. quantumgirl | | #4

      Russel, why a full 12”?

  2. Expert Member
    Peter Engle | | #2

    You can also wrap the entire lower edge of the system with window screening. Start by tacking it to the WRB, install the foam and strapping for the siding, then wrap the screening up and tack to the strapping before installing the siding. The screening keeps critters out while allowing air circulation and water drainage. Use fiberglass or bronze screening for durability.

  3. Expert Member
    Malcolm Taylor | | #3

    quantum girl,

    If you are including a rain-screen cavity on the wall you want to provide both drainage and ventilation at the bottom. The most durable solution is to use perforated metal J channel bent to cover both he foam and wood furring. Something similar to this:

  4. quantumgirl | | #5

    Thanks y’all! I already purchased Cor-a-vent siding vent for the rain screen. So I assume I really only need to wrap the bottom of the foam, not the rainscreen gap?

  5. quantumgirl | | #6

    I have a follow up question. Hopefully someone can chime in.
    I’m finding pictures of different ways to bend the coil stock. Some show a little lip that goes back up over the front side of the foam while the other image shows that lip is bend downwards. I’d assume I would get a better protection from bugs chewing the foam with the lip bend up, but wouldn’t that prohibit water from draining out if it ever gets behind the foam?

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