I have a need (long story) to use a long strip of 3/8" plywood under a door casing vertical piece and I plan for it to be slightly wider than the casing. It is joining old lathe and plaster and, for a long and irrelevant set of reasons (I must mention this because I know how some of you like to challenge principal designs), I cannot use drywall.

So if I have about an inch of plywood sticking under door casing, will it be possible (meaning adhere and look like) drywall? I know that it's possible to mud over plaster to iron out uneven spots but not sure if it works when applied over plywood.

  • How thick is the lath? I'm wondering if your best bet is to use the plywood as a lath-substitute and then basically plaster over it... Commented Apr 1, 2016 at 2:17
  • It's 3/8" and there are reasons why that's not feasible
    – amphibient
    Commented Apr 1, 2016 at 2:35
  • Since this isn't answering the mud question I'm not posting it as an answer: sand it pretty smooth and then add a few coats of primer followed by a few coats of paint with a roller will get you should have a fair finish.
    – jqning
    Commented Apr 1, 2016 at 3:53

1 Answer 1


yes - we do it from time to time. just make sure you put mesh tape on the wood and on to the adjacent drywall or plaster before you mud

  • So you're saying the mud does adhere okay to plywood ? That's my main concern
    – amphibient
    Commented Mar 31, 2016 at 21:14
  • 2
    adheres just fine. if you are worried about bond strength, just add bonding admixture to your mix and mechanically roughen the plywood. we have never had any issues bonding to spruce rough plywood. Commented Mar 31, 2016 at 21:16
  • 1
    The only concern is movement in the wood due to varying humidity. Using mesh tape and nailing or gluing the plywood securely should result in success.
    – isherwood
    Commented Mar 31, 2016 at 21:18
  • The better grade the plywood is usually the more oil/coatings they have on the outter veneer to make it look better and so it doesn't splinter. Mud does not adhere well to this at all. You can just go over it with a coat of primer or sand it down - either way works. Also I would use mesh tape here - this stretches better and makes you put an adequate amount of mud to hide seam.
    – DMoore
    Commented Mar 31, 2016 at 22:01
  • BTW, i'm just done doing this and it worked. Thanks !!
    – amphibient
    Commented Jun 24, 2016 at 16:29

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