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Exterior tongue-and-groove trim question

kevinjm4 | Posted in General Questions on

Regarding pre-primed KD tongue and groove cedar trim: I ripped 1×6 pieces into even thirds, and there was significant bowing/crooking right after I did that. Before ripping, the boards were straight as an arrow.

theres nothing in the manufacturers warranty or installation instructions that prohibit ripping.

generally speaking is ripping t&g not a good idea?

i went slow-ish, it’s cedar after all, and had a nice diablo 60 (or maybe it was 40…) tooth blade on my saw…

if the the company will not honor any sort of warranty claim I am not opposed to installing them but was wondering… if I work hard to bring them back to straight upon install, will they be prone to splitting or something else if they’re fastened under pretty good pressure like that?

the amount of movement was anywhere from 3”-12” in 8’ of board after ripping. I know this is probably hard to speak to but any input appreciated.

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Replies

  1. seabornman | | #1

    There can be balanced stresses in boards that become unbalanced when you cut them. It can be frustrating. However, that size of board should be easy to bend back to straight as you nail it in place. I don't believe you'll have any problems with them. Are you using ring-shank siding nails? I've found they will hold most boards in place.

    1. kevinjm4 | | #2

      Yeah I was going to use 15g finish... but now will consider something else, either crown staples or siding nails... that’s frustrating though because these are now .75” x 1.75” shouldn’t need much to hold them, but I hear you...

  2. GBA Editor
    Brian Pontolilo | | #3

    Hi Kevin.

    I don't understand wood science enough to explain why it happens, but your experience ripping the boards is common. I am curious what are you using this material for?

  3. kevinjm4 | | #4

    Battens. For board and batten siding. In my opinion 1x3 too big - aesthetically speaking, and 1x2 too small not forgiving enough at board joints to cover the nails on both boards.

    1. Expert Member
      MALCOLM TAYLOR | | #8

      " In my opinion 1x3 too big - aesthetically speaking, and 1x2 too small "

      Sometimes it seems to me it's as though we have a visual memory of c0mm0n dimensional sizes, and when we see them on a building we go "Oh - they used 1 x 4s". Cutting any trim to a non-nominal size seems to be more satisfying for some reason.

  4. GBA Editor
    Brian Pontolilo | | #5

    I'm wondering if I'm misunderstanding your terminology. Do you mean finger jointed pre-primed cedar? Tongue-and-groove boards have a tongue running down one long edge of the board and a groove running down the other edge and are commonly used for flooring, paneling, siding, etc. A lot of pre-primed exterior trim today is finger-jointed allowing the mills to make long straight boards from smaller pieces of wood.

    1. kevinjm4 | | #6

      Yes I’m sorry finger jointed!

  5. GBA Editor
    Brian Pontolilo | | #7

    That's what I thought.

    And I think joel is right that you shouldn't have trouble straightening your rips during installation.

    One caution: Make sure you prime those pieces really well before you install them. In my experience and the experience of many builders who I have talked to about this, finger jointed boards do not like moisture. I recommend two good coats of primer on all six sides.

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