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Community and Q&A

Should I caulk the bottom of vertical cedar siding?

jvm | Posted in Energy Efficiency and Durability on

A contratoor who replaced some wood pecker damaged vertical cedar siding boards recommended that I caulk at the bottom of the lowest boards as a way to lessen air inflitration into my home. House was built in 1987 and has Celotex sheathing on the outside of the stud walls with the cedar siding over that. I think that caulking as he recommends will only trap water behind the siding that can get in where the boards overlap.

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  1. silkwj | | #1

    As someone who just fixed cedar clapboard (horizontal) that had peeling paint all over and rot in one corner due to water trapped behind it (so we converted it to a back-vented rainscreen), I wouldn't caulk it. Siding isn't supposed to be the air barrier, only bulk water management (aka rain). It should have the ability to let minor leaks dry out.

  2. GBA Editor
    Martin Holladay | | #2

    I agree with Cramer. While you can establish an air barrier at the sheathing level, you don't want to try to make your siding airtight.

  3. wjrobinson | | #3

    I third the motion, no caulk.

  4. roofnron | | #4
  5. GBA Editor
    Martin Holladay | | #5

    According to the document that Ronnie linked to, "Do not caulk areas that will prevent moisture from escaping the wall cavity."

  6. jvm | | #6

    Thanks. You all confirmed my thoughts.

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