# have seen mixed views on caulking under clapboards



## beautify (Apr 14, 2008)

I would love to see a discussion on this matter of caulking under clapboards.. some people say no.. so the house can breathe.. others say yes to keep moisture from penetrating.. wondering what people think..thanks


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## johnpaint (Sep 20, 2008)

beautify said:


> I would love to see a discussion on this matter of caulking under clapboards.. some people say no.. so the house can breathe.. others say yes to keep moisture from penetrating.. wondering what people think..thanks


Not good to do it, but to say I haven't would be a lie. If you are painting with white or very light color if you leave the cracks not caulked the black crack looks very unsightly as you look up at the siding, so your kind of caught between a rock and a hard place. Also sometimes the siding has shrunk leaving a rough unpainted siding below.


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## beautify (Apr 14, 2008)

*thnks*

yeah.. I will be using a darker blue stain.. so the crack wont be as noticeable.. but the whole house is not clapboarded.. the other side of the house is cedar shingled.. so can it still breathe that way..


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## DeanV (Apr 18, 2007)

Never, unless there is some special problem you are trying to deal with. Water will not enter from the bottom edge and as the wood expands and contracts, that edge will look awful in time if you caulk it.


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## daArch (Mar 15, 2008)

beautify said:


> I would love to see a discussion on this matter of caulking under clapboards.. some people say no.. so the house can breathe.. others say yes to keep moisture from penetrating.. wondering what people think..thanks


Never have.

How moisture would penetrate up under uncaulked clapboards is unclear to me. The calpboard overlap prevents this - unless you live in an area with UP winds


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## tsunamicontract (May 3, 2008)

yah definitely do not put your caulk in that crack

moisture problems await you. They actually make products to open up the gaps under clapboards to allow more breathing (ie. wedgevent)


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## chrisn (Jul 15, 2007)

They actually make products to open up the gaps under clapboards to allow more breathing (ie. wedgevent)

I was told ( don't remember who) by someone on another board about 6 or7 years ago to never caulk under there. In fact to remove previous caulking and install the wedge-vents. I was doing an exterior at the time where paint was actually bubbling off the siding and could not figure out what was going on. I had the Duron rep out with a moisture meter and what it came down too was that this woman's house was sealed up tight as a drum and moisture was literally coming out of the siding as there was nowhere else for it to go( so I was told). Removed all the caulking,installed wedge-vents( at great expense to the HO), still looks good today. In fact I did the same to my own house the next year as the old redwood keep popping off the paint, it is still popping paint but not as bad.
Man, my fingers are sore from typing.


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## Wolfgang (Nov 16, 2008)

^^^ That has got to be the longest post I've ever seen Chris type and post. I always thought he was just a man of few words. Another Paint Talk myth shot to heck...


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## EricTheHandyman (Jan 29, 2008)

DO NOT CAULK IT!! That gap under the clapboards is part of the moisture drainage plane, it allows any moisture the gets behind the siding to escape or dry out. Use the wedge vents or a similar product, or just leave the gap.


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## johnpaint (Sep 20, 2008)

I think we are in consensus that there should be no caulking on the lap area. It a good idea to let the home owner know about why you are leaving the crack.


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## chrisn (Jul 15, 2007)

I always thought he was just a man of few words.

I am!


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## ParagonVA (Feb 3, 2009)

I need more than two thumbs to agree with you guys, because this is an unmistakable given. :thumbup::thumbup:


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## Last Craftsman (Dec 5, 2008)

daArch said:


> Never have.
> 
> How moisture would penetrate up under uncaulked clapboards is unclear to me. The calpboard overlap prevents this - unless you live in an area with UP winds


What about my submarine? I used clapboards instead of steel for the skin to save some money.

Should I still try to let them breathe? Or should I seal them up?

:whistling2:


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## bikerboy (Sep 16, 2007)

here is one I looked at Monday. Yes, the bottom joints were caulked. 

"The guy who did all our interior painting did it." Said the H/O. "We called him, but he is out of business." 

Slipping out before I could stop: "I can see why!"


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## bikerboy (Sep 16, 2007)

This was coated in 2005 with BM oil primer and Sikkens Rubbol.

The only areas not failing are behind the bushes.


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## MAK-Deco (Apr 17, 2007)

bikerboy said:


> This was coated in 2005 with BM oil primer and Sikkens Rubbol.
> 
> The only areas not failing are behind the bushes.


in 05 is that when Sikkens recalled a lot of Rubbol??


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## nEighter (Nov 14, 2008)

BB.. I think that is more crappy siding than a crappy paint job.


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## johnpaint (Sep 20, 2008)

It's hard to keep paint on that smooth siding anyway as you know. What are you going to do with this one?


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## plainpainter (Nov 6, 2007)

Thats just balls to walls raw water intrusion getting behind the clapboards - you see it more on the eaves side of home - but even on gable ends where the rakes sides of the roof don't extend a foot or so past the wall - or there is no drip edge - and sometimes it's just flat out impossible to figure out how the water gets behind there.


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## 4ThGeneration (Apr 17, 2007)

The guy must have been a painter for 20 years. Meaning: He painted his house once a year if it needed it or not :blink:

Somebody said they did not know how water can get behind clap board? All you need is wind driven rain. You can not predict what wind will do, but it does blow up also. All that water or algae needs is a hair line crack to get in and infiltrate. It will be a breeding ground for mold and rotting.

I have seen the problems with exterior paint jobs that have had this done, but what about the interior. Since the conventional paint can not breathe and the claps were caulked there is but one way for the moisture to go and thats inside. Send some pics of that for us.


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## bikerboy (Sep 16, 2007)

in 05 is that when Sikkens recalled a lot of Rubbol??
__________________
I do not know?

BB.. I think that is more crappy siding than a crappy paint job.

It's cedar siding. Just standard stuff. Whoever installed it even put copper flashing under each butt joint. Although some will have to be replaced now.

It's hard to keep paint on that smooth siding anyway as you know. What are you going to do with this one?

I was planning to walk on this one. Priced it accordingly. (siding replacement is extra) Got an email this morning that they want me to do it AND install wedge vents. I am torn. Take the money, or pass on the headache. 

Did tell the HO that I would not do it until they had an inspector come out and check for leaks.

Thats just balls to walls raw water intrusion getting behind the clapboards - you see it more on the eaves side of home - but even on gable ends where the rakes sides of the roof don't extend a foot or so past the wall - or there is no drip edge - and sometimes it's just flat out impossible to figure out how the water gets behind there.

Because of the way it is peeling, I thing it is just condensation being drawn through the wood by sunlight. Since it was caulked tight, there was no chance of it evaporating out through the bottom of the boards. 

You can't see it in the pics, but the coating is in good shape behind the bushes. (which escapes the brunt on sunlight)


Somebody said they did not know how water can get behind clap board? All you need is wind driven rain. You can not predict what wind will do, but it does blow up also. All that water or algae needs is a hair line crack to get in and infiltrate. It will be a breeding ground for mold and rotting.

I have seen the problems with exterior paint jobs that have had this done, but what about the interior. Since the conventional paint can not breathe and the claps were caulked there is but one way for the moisture to go and thats inside. Send some pics of that for us.

Seeing as this house is only a couple of blocks from the Chesapeake Bay it is subjected to violent storms. As are most of the homes in the area. Is it possible that the wind blows across the ground and runs up the siding. It is also possible that Jack Paul is the smartest and best painter ever to have walked the earth. But both are somewhat unlikely.

Sorry that I cannot honor your request for inside pics.


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