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Does it have to be tongue & groove ceiling on beams?

Schnef | Posted in General Questions on

building a cottage that is going to have to remove 3 very large red oaks.  looking at a structure w gothic arch beams, and would love to use “persist method” w wood planking then a hot roof build   Would love to lumber out my red oaks, but concerned that tongue and groove is required for the ceiling.  is it? zone 5a, thanks, Tom

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  1. Expert Member


    There are two different parts to the answer:

    From a structural point of view T&G help spread loads, so for a comparable span between the beams you would need thicker lumber if it wasn't grooved. But if you are getting it milled, having it a bit thicker won't matter.

    If you don't have a T&G to overlap between boards, gaps will appear seasonally. You need to have a strategy for this purely from an aesthetic point of view. Some sort of backing so you aren't looking up at something unsightly.

  2. GBA Editor
    Martin Holladay | | #2

    When I was a young man without much money, I built a ceiling like the one you describe. (I'm still living in the house.) The joists are a mixture of spruce and fir logs with the bark removed, flattened on one side with an adze. The subfloor above consists of rough-sawn spruce boards, without tongues or grooves.

    I installed asphalt felt above the subfloor, under the flooring (hardwood flooring recovered from a demolition site). As Malcolm correctly noted, the subfloor dries out in winter, and there are gaps between the boards. No one notices. It's a rustic look, but it works for me.

  3. Schnef | | #3

    Thank you both! Your thoughtful and timely responses are amazing!

  4. tommay | | #4

    Well if you are milling your own boards, I would think a simple bevel on each side would work. Small staple nail or adhesive between joints for some overkill.

    1. Expert Member
      MALCOLM TAYLOR | | #5


      A bevel might hide the gap, but tying the boards together with adhesive or nails is a bad idea. It leaves no mechanism for seasonal movement. If the adhesive is strong enough to keep the boards together, it is the boards that will crack.

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