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Community and Q&A

Taping Bottom Seams of Exterior Foam Insulation

bonai | Posted in General Questions on


I understand the seams of the insulation boards need to be taped. I already have the bottom seams of the OSB sheathing taped with the concrete of the foundation. Do I have to tape the bottom seams of the insulation boards to the concrete? I think the answer is yes, as we want to reduce air leak.

I have seen people using regular vapour barrier tape… My plan is to use the Siga wigluv tape for that, as it is exterior/rain rated and…I am building a rain screen… Am I overdoing it?

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  1. Expert Member


    - Are you using the insulation as your WRB?
    - What is your primary air-barrier?

  2. bonai | | #2

    Blueskin VP 100 is the primary WRB.
    Im quite confident both type of tape will initially stick on the foam boards, especially that they are covered with a poly film. But overtime, the normal vapour tape is not exterior/rain rated... Thats why I am thibking to spend more and go with the Siga tape.

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