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Community and Q&A

Redundancy of taping and caulking XPS

Daniel F. Vellone | Posted in General Questions on

On my wrap and strap I’ll be taping joints on the xps with siga sicrall. Will caulking the joints in addition be an unnecessary redundancy that I can save some money by avoiding?

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  1. Steve Knapp CZ 3A Georgia | | #1

    Are you doing one layer or two? With two you could alternate the layers and have much less risk of gaping. Also, I believe the Siga Sicrall is only intended for interior use (unless it's been altered from a few years ago).

  2. Daniel F. Vellone | | #2

    One layer. I purchased reclaimed material that came in 2.5" thickness that satisfied my requirement. I selected siga sicrall based on the comparison conducted here on Martin Holladay's Backyard Tape Test.

  3. Steve Knapp CZ 3A Georgia | | #3

    I checked the Siga site and Sicrall is only for interior use. Martin added an update on that point, but you may missed it.

  4. Daniel F. Vellone | | #4

    I did read the reference to it being for interior use, but he also noted that in spite of that it outperformed any of the other tapes. It's also getting covered with house wrap and siding so it won't be exposed to weather.

  5. GBA Editor
    Martin Holladay | | #5

    This is a judgment call. You have to decide what matters most to you -- saving money, or the peace of mind that comes from redundant systems.

    My own decision would depend on the size of the gaps. If you are using reclaimed material, and there are occasional gaps that are significant, it would make sense to fill the gaps with caulk or canned spray foam. But it's your house -- you get to make this judgment call.

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