# Caulk between boards (board and batten siding)



## Ron6519 (Mar 28, 2007)

I would not use a 1/4" plywood panel for a siding material. It's too thin. 
Do they even make an exterior ply that thin?
Ron


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## Briandl (Jul 17, 2010)

That's helpful.

Anybody else?


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## rock16 (May 14, 2010)

If you caulk the battens the seam will be sealed behind them, so there is no need to caulk the seam.


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## Briandl (Jul 17, 2010)

That certainly makes sense. I've read some things that indicate it would be not bad but redundant, but at the same time I've read stuff that indicates you shouldn't block that channel because it allows water to escape and expansion and contraction between the boards, not that caulk should affect that greatly.


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## Gary in WA (Mar 11, 2009)

If the structural panels under the battens are side lapped at the joint there is no reason to caulk them.* Individual* boards (and battens) should not be caulked for expansion/contraction.

Gary


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## MotoXXX (Sep 8, 2011)

GBR in WA said:


> If the structural panels under the battens are side lapped at the joint there is no reason to caulk them.* Individual* boards (and battens) should not be caulked for expansion/contraction.
> 
> Gary


So are you saying you shouldn't use caulking at all on boards or battens either one? I am about to replace several pieces of both on my house and I was told to caulk both edges of every batten, even the exsisting ones that I am not replacing. Thanks in advance for your help!


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## ddawg16 (Aug 15, 2011)

Briandl said:


> That certainly makes sense. I've read some things that indicate it would be not bad but redundant, but at the same time I've read stuff that indicates you shouldn't block that channel because it allows water to escape and expansion and contraction between the boards, not that caulk should affect that greatly.


The tar paper underneath is the escape route for water....if you have water coming 'out' of the boards...you have some major issues.



GBR in WA said:


> If the structural panels under the battens are side lapped at the joint there is no reason to caulk them.* Individual* boards (and battens) should not be caulked for expansion/contraction.
> 
> Gary


I agree....But then again, I would not want siding on my house made of plywood.....

My 50 year old house has vert lap boards (6") in the front...all are in perfect shape....when properly painted, water does not get in....and the narrow size reduces the effects of expansion and contraction.....


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## Tom Struble (Dec 29, 2008)

my experience has been most surface caulking details usually fail sooner or later,usually i'm not to concerned with trying to seal vertical members


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## Gary in WA (Mar 11, 2009)

MotoXXX, no caulking. Leave room for expansion/contracting with the seasons, the battens only hide the gap for appearance sake as the boards width changes; http://www.buildingscience.com/documents/insights/bsi-023-wood-is-good-but-strange/

Plywood "boards" will change very little. Plywood surface dries, OSB is another story.....

Gary


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## MotoXXX (Sep 8, 2011)

GBR in WA said:


> MotoXXX, no caulking. Leave room for expansion/contracting with the seasons, the battens only hide the gap for appearance sake as the boards width changes; http://www.buildingscience.com/documents/insights/bsi-023-wood-is-good-but-strange/
> 
> Plywood "boards" will change very little. Plywood surface dries, OSB is another story.....
> 
> Gary


Thanks Gary, mine are actually rough sawn boards but I don't know if they are cedar or what as I haven't removed any of the bad ones yet. I do know they used alot of cedar when they built this neighborhood in the late 50's but I believe the front and sides of my house that are bats & boards is not the original siding as the rear of the house are cedar shingles as many homes in this area are that have not remodeled.


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