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Community and Q&A

Caulk removal under lap siding

byyman63 | Posted in Green Building Techniques on

My carpenter caulked the bottom border of my lap siding exterior wall insisting it should be done. Can I leave the siding caulked,  and if not, how can I break the seal on the caulk? 

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  1. GBA Editor
    Brian Pontolilo | | #1

    Hi byyman63,

    I have always understood caulking the bottom of lap siding to be a bad idea and witnessed a very fast failure a few years ago when the painters did this to a house next door to mine. This is anecdotal, of course, and it's only one case, but within a few years of the siding being caulked and painted, the paint was peeling off in sheets.

    As far as removal, which isn't easy if the caulk adhered well, I've always used a putty knife that I can run at a low angle across the caulked surface to avoid damage. I bet you'll get some more tips for removal from other GBA members.

  2. byyman63 | | #2

    Thank you for the reply Brian. I hope I do get other input from the members.

  3. Expert Member
    BILL WICHERS | | #3

    If you’re lucky, the caulk won’t be adhered very well. If that’s the case, VERY carefully lift the caulk bead somewhere. I usually use either a sharpened putty knife (sometimes the “flex” kind works better than the “stiff” kind here since you can squish the flex kind to get it tight to the material you’re scraping), or one of the razor blade holder gizmos usually used for scraping paint off of glass. Once you have the bead lifted, you can sometimes carefully pull it off like a “caulk rope”. It’s all about the angle while doing this, you need to get it just right so that it doesn’t stretch too much and break but still pulls off cleanly. After some trial and error you’ll get a feel for is “right” for your particular project.

    If the caulk DOES adhere well, you have a lot of tedious scraping to do. I’d use the same tools I mentioned above, and maybe a nylon bristle brush too. Acetone will usually help to get caulk off, but it will also usually mess up any finish on whatever the caulk is stuck to so use it with care if you use it at all.


    1. byyman63 | | #4

      Thank you for the reply Bill. That helps. I just wonder if it is essential to remove it.

      1. Expert Member
        MALCOLM TAYLOR | | #5


        Theoretically at least, lap siding should shed any water that gets behind it at each course, so you are only really worried about moisture trapped by the bottom piece. Having it caulked isn't ideal, but it also isn't something that on its own should be much of a problem.

        1. byyman63 | | #6

          Thank you for that opinion. Very much appreciated. I have spent a lot on this house and would not want to lose on a technicality such as caulking in the wrong places.
          Much appreciated again.

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