Lots of cold air coming through a variable narrow - about 1-2 cm (0.5 in) - gap between a wooden beam and the concrete wall in the basement (image 1 below).

  1. What can I fill it with? Worried about moisture collecting and eventually ruining the beam.

  2. Noticed that on another beam a similar spot was treated with something (picture 2); there is even a solidified translucent amber-like drop clearly visible on the picture. What can this material be?

  3. Right next to it there's aluminum ducting going into the same wall treated with expanding foam; there is a layer of wood on top of the wall so concrete itself is not visible (picture 3). Can I just fill the gap with similar stuff?

gap between a wooden beam and concrete basement wall

mysterious material filling a similar gap

dryer duct going into wall, gap filled with expanding foam

  • 1
    Look u[p "spray foam insulation". Whether it meets your needs and local codes is an open question. Commented Feb 16, 2020 at 1:35
  • @DrMoishePippik This is a relatively small gap a few inches long, I don't understand how spray foam insulation would be relevant here. Commented Feb 16, 2020 at 22:13
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    "Worried about moisture collecting" With a draft, any moisture will dry up. If you seal it...you may be trapping moisture in. Hopefully you can seal both sides. Commented Mar 11, 2020 at 4:49
  • @SteveWellens good idea - but only in the spring! Commented Mar 13, 2020 at 1:45

1 Answer 1


The amber stuff looks like construction adhesive. Particularly Liquid Nails.

If the void is not load bearing and protected from moisture, then you can fill it with just about anything. The foam filler is a good choice since it's easy to use

  • Thank you for answering! What would be an example of protected from moisture? Commented Mar 17, 2020 at 16:24
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    It's the not obvious ones to pay attention to: The obvious is proper wall covering to protect from rain. Not obvious is keeping soil grade lower the the top of foundation, and sloped away at the exterior of the building. And a barrier between the wood and concrete. In your case, it looks like your house is older and that barrier likely isn't there but you also have the test of time. My statement is to CYA us both and to separate the issues, the drafting and gaps, and any water/moisture/rotting issues
    – Ack
    Commented Mar 17, 2020 at 17:51

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