# Caulking between Clapboard?



## JJSPS (Jun 29, 2011)

Getting ready to paint exterior clapboard on house and need to learn about caulking gaps between clapboard peices. I've heard several different thoughts from seal the verticle gaps between pieces to leave open for breathability. Gaps are 1/8 - 1/4 inch wide. My concern is if not sealed will weather enter and cause damage long term? Any professional advice? Thanks


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## Gymschu (Dec 12, 2010)

I have done it both ways. The experts say NOT to fill the cracks so the house can breathe. I usually fill the cracks especially if they are unsightly. I think houses breathe just fine with the cracks filled. After all, clapboards usually overlap anyway, right? Anyway, I have houses that I did 10 years ago and the paint is still decent, the house isn't sweating on the inside, everything turned out fine. Just your preference I would say.


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## Workaholic (Apr 1, 2007)

I typically try not to caulk the horizontal because wood expands and contracts with the temp, so when you caulk the horizontal it is more prone to cracking and look like crap.


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## Gymschu (Dec 12, 2010)

Workaholic said:


> I typically try not to caulk the horizontal because wood expands and contracts with the temp, so when you caulk the horizontal it is more prone to cracking and look like crap.


Workaholic, yes, it can end up looking like crap, but most of the houses I have done this on the caulk stays put for at least 7 years and by that time it's time for paint again. I guess you pick your poison.......look at the unsightly cracks or take your chances with the caulk.


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## chrisn (Dec 23, 2007)

JJSPS said:


> Getting ready to paint exterior clapboard on house and need to learn about caulking gaps between clapboard peices. I've heard several different thoughts from seal the verticle gaps:no: between pieces to leave open for breathability.:yes: Gaps are 1/8 - 1/4 inch wide. My concern is if not sealed will weather enter and cause damage long term? Any professional advice? Thanks


 
I vote no cualk


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## JJSPS (Jun 29, 2011)

Thanks for the advice, guess if the gaps bother me enough and i'm really ambitious the gaps will get caulked. Appreciate the comments from all.


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## jschaben (Mar 31, 2010)

JJSPS said:


> Getting ready to paint exterior clapboard on house and need to learn about caulking gaps between clapboard peices. I've heard several different thoughts from seal the verticle gaps between pieces to leave open for breathability. Gaps are 1/8 - 1/4 inch wide. My concern is if not sealed will weather enter and cause damage long term? Any professional advice? Thanks


 
Depends on what you're painting with to some extent. First house I ever owned I painted with Glidden Gel-Flo. At the time a fairly decent quality oil based enamel. I also proceeded to seal up and caulk anything that looked like it could possibly let moisture in. A year and a half later, I was repainting over the bathroom and the kitchen:furious:. What I had failed to consider was air movement behind the clapboard to allow for moisture to escape. Humidity from the kitchen and bath simply moved through the wood and pushed the paint off.


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## housepaintingny (Jul 25, 2009)

We don't caulk under the clapboards. The substrate needs to breath and oisture needs to be able to escape. Only if there are vents or wedges in the clapboard would I caulk under them.


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## kwikfishron (Mar 11, 2010)

JJSPS said:


> Getting ready to paint exterior clapboard on house and need to learn about caulking gaps between clapboard peices. I've heard several different thoughts from seal the verticle gaps between pieces to leave open for breathability. Gaps are 1/8 - 1/4 inch wide. My concern is if not sealed will weather enter and cause damage long term? Any professional advice? Thanks


Yes, caulk the vertical gaps (butt joints) of your wood or FC siding. :yes:


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## MiTmite9 (Feb 23, 2015)

*Don't invite moisture to remain in the walls of your house*

My builder friend, a guy who has been in the trade for nearly 40 years, took me outside today and showed me WHY NOT TO CAULK when your old house (mine is 1904) has "beveled siding" aka clapboard.

Our painter went crazy with the caulk, the job was beautifully done. The new paint is all on the East side of the house and gets full sun from sunrise until noon. Guess what? Not even six months later and this old house is telling us it HATES the caulk. Looks terrible, with the caulking all cracked and even a few old boards are cracking now, too. Sun/moisture causes the wood to expand and contract. The caulking refuses to budge and that means trouble.

The painter is a top-notch painter, known him 25 years. But guess what? His insistence on caulking means the house cannot BREATHE! Plus rain will run down and collect at the bottom of the window corners, because he caulked all that as well. Hello, wood rot and mold. Now the caulking has to be removed (a hellish job!) and all on my dime. 

I visited this site as part of my "evidence-gathering, " since my painter just won't listen to us about knocking it off with all the caulking! The house is telling us to stop, you can see that plain as day.

There's a reason this old house of mine was a-okay for over 100 years. Now we goofed up and she needs a ton of extra TLC and no more sealing up her "lungs." DO NOT CAULK!


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## Matthewt1970 (Sep 16, 2008)

Caulk is not going to keep the house from breathing. When siding is new it typically is a tight joint between boards. No breathing issues then. And I certainly hope we aren't replying on gaps in out wood for our house to breath.


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## Jmayspaint (May 4, 2013)

Matthewt1970 said:


> Caulk is not going to keep the house from breathing. When siding is new it typically is a tight joint between boards. No breathing issues then. And I certainly hope we aren't replying on gaps in out wood for our house to breath.


Yeah, but old houses are different than new houses. They didn't use vapor barriers, etc in the old days. And most old houses already have so many coats of paint that the permeability has dropped to near zero anyway, caulking them up tight can tip the scales to a peeling disaster.


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## Matthewt1970 (Sep 16, 2008)

Jmayspaint said:


> Yeah, but old houses are different than new houses. They didn't use vapor barriers, etc in the old days. And most old houses already have so many coats of paint that the permeability has dropped to near zero anyway, caulking them up tight can tip the scales to a peeling disaster.


But even old houses had new siding at one point.


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## chrisn (Dec 23, 2007)

Matthewt1970 said:


> But even old houses had new siding at one point.


mine did (does) not, nor do 90% of any old houses I have ever painted

maybe it depends on location?


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## housepaintingny (Jul 25, 2009)

We do not caulk under clap boards where they over lap each other, but we do caulk where all trim meets siding, as needed, windows/doors etc and at the but joints if they have larger gaps. I've seen first hand, especially on older homes that have been sealed up/everything has been caulked by previous painters and eventually the paint fails a lot sooner then it should, along with other issues.


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## Matthewt1970 (Sep 16, 2008)

chrisn said:


> mine did (does) not, nor do 90% of any old houses I have ever painted
> 
> maybe it depends on location?


Your house was new at one time and they typically don't put used siding on new houses. By the logic presented here unless your house has gaps in the siding it isn't breathing properly and you typically don't have gaps in your siding for many, many years.


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## paintdrying (Jul 13, 2012)

what about that whole business of pounding those little wedges between the boards so the house can breathe?


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## housepaintingny (Jul 25, 2009)

mj12 said:


> what about that whole business of pounding those little wedges between the boards so the house can breathe?


Wedges for clap board siding will help moisture to escape and help to prevent early paint failure and other moisture issues.


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## chrisn (Dec 23, 2007)

mj12 said:


> what about that whole business of pounding those little wedges between the boards so the house can breathe?


I have done that on my own house about 10 years ago and it still does not need painting, previously it would be peeling after 3 or 4 years


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