Tongue and Groove over 6" wide - need advice on best way to keep them from cupping/moving

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Forum topic by woodengaragedoorguy posted 12-28-2012 02:17 PM 2549 views 0 times favorited 8 replies Add to Favorites Watch
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7 posts in 1977 days

12-28-2012 02:17 PM

I put a nice sized bead of exterior wood glue to the garage door frame, trowel it, then apply tongue and groove material piece after piece. I use 1-1/4” divergent staples which work great for holding power. Most of the tongue and groove lays pretty flat to the garage door frame but I have noticed that when I start using tongue and groove wider than 6” I sometimes see that material cupping slightly. Note* these materials are glued up with 2 glue lines (3 pcs total making that one piece of TGV). I know I could screw the center of each piece and then use a wood plug to fill then sand smooth. But does anyone have any tips on a type of glue, or fastener method to where I could get these materials flush and have less cupping? All wood that I use is below 10%.
Thank you,

8 replies so far

View Tyler's profile


52 posts in 1982 days

#1 posted 12-28-2012 02:43 PM

you could try putting a type of backer board or furring strip and attach it.

-- You can get alot further with a kind word and a hand gun, than just a kind word alone

View Don W's profile

Don W

18686 posts in 2537 days

#2 posted 12-28-2012 03:08 PM

I wonder if its cupping because its glued to tight? Wood needs to move, and your not going to stop it short of some sort of permanent seal. The reason for tongue and groove is to allow for the expansion and contraction. That’s why smaller pieces don’t cup, there is enough joints to allow for the movement.

Try incorporating some sort of break, like a seam. Use a tenon type piece maybe and let it slide.

-- - Collecting is an investment in the past, and the future.

View bondogaposis's profile


4690 posts in 2321 days

#3 posted 12-28-2012 03:11 PM

Using quarter sawn material will prevent cupping. Flat sawn will always want to cup to some degree. You really can’t stop it other than using a stable material like plywood.

-- Bondo Gaposis

View Bernie's profile


422 posts in 2807 days

#4 posted 12-28-2012 04:25 PM

I’m thinking along the same line as Don and Bondo. Too much pressure on the clamps will cause cupping and the other issue of wood movement, especially on a garage door but you probably know this already since your statement of “all wood is 10%”.

There is one adhesive you might want to try. I was introduced to it by my wood working guru who claims this stuff will not turn hard, yet it holds better then wood glue. It’s called “LOCTITE”

-- Bernie: It never gets hot or cold in New Hampshire, just seasonal!

View joeyinsouthaustin's profile


1294 posts in 2042 days

#5 posted 12-28-2012 05:33 PM

We run into this problem with exterior siding. One side in sun and humidity, one in shade. Do the pieces have any kind of back cut?? (like flooring) this can relieve the pressure on the front side. Also, when we have milled ourselves, we always try to install with the natural cup crowned to the shade side. That way it will tend to flatten when warmed on one side only. +1 on leaving room for expansion. also +1 Bernie In glued applications like this, we use a urethane glue, like flooring, or PL. It will allow for movement.

-- Who is John Galt?

View MonteCristo's profile


2099 posts in 2158 days

#6 posted 12-29-2012 12:12 AM

Wood moves. Especially in an exterior situation, where humidity and temperature swing a lot more. Try and glue or screw it to stop the movement and it will likely split.

-- Dwight - "Free legal advice available - contact Dewey, Cheetam & Howe""

View Bernie's profile


422 posts in 2807 days

#7 posted 12-29-2012 03:37 AM

Hey Joe – just went down to the workshop and the LOCTITE I mentioned is a urethane glue used in flooring and “PL” is on the tube. From what you are saying, my guru is right as usual. It’s been about 6 months since I first used it and no problem thus far… with your comment, I’m in the relax mode now… thanks!

-- Bernie: It never gets hot or cold in New Hampshire, just seasonal!

View pintodeluxe's profile


5626 posts in 2783 days

#8 posted 12-29-2012 07:12 AM

Maybe a picture or two would make it easier for us to help you.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

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