# Cracked splitting cedar siding



## Wisco (Jun 18, 2008)

I have a 12", 25 year old, lap, rough cedar siding on the large 2 story west facing side of my home. Restained 4 1/2 years ago otherwise in pretty good shape. There are 10-15 percent of boards with longitudinal deeper open grain in them, not all the way through but it looks like cracks from natural movement and weathering. There are a couple others with splits for a foot or so but otherwise I am just triing to keep up with maintanence on this abused side of my home.

What is the most permanent way to address these problems besides replacing the boards at 3.50 a linear foot.

Let me add when I restained the west side 4 1/2 years ago I used gorilla glue in spots and it has held up very solid without any splitting or movement. Used PPG Ultra stain and plan on maybe using Duration paint now. Thank you


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## Nestor_Kelebay (Jun 17, 2008)

Dunno if you can paint over a solid stain. Hopefully someone else will know.

The splitting at the ends of boards that are exposed to the elements is due to the non-uniform absorbtion of moisture into wood. Basically, the end grain of wood both absorbs water (and other liquids, like wood stains) a full 15 times faster (and I think, 15 times as much) as through any other part of the exposed wood.

When a board gets rained on, the moisture is most rapidly absorbed at the end grains of your boards, and quickly disperses into the wood from there. Then, the wood starts to dry, and it loses moisture 15 times faster at the end grain, too. Since wood cell walls shrink in thickness as the wood dries, you can get tremendous tension in the end grain of a board because the wood cells there want to shrink in thickness, whereas the wood further from the end of the board doesn't want to shrink. The result is that the board splits at it's ends. This is precisely the reason why every 2X12 in the lumber yard will be split for about a foot to 18 inches from it's end.

If you have any exposed end grain on your cedar siding, I would paint that end grain with an exterior high gloss oil based paint to prevent the swelling and shrinking.

Also, I would take a tube of any latex or "acrylic" caulking and fill those splits with that caulk before priming and painting (or staining). Latex, or "acrylic" caulks are the same as latex paints in that they will allow individual water molecules to evaporate out through the paint, but won't allow liquid water to get into the wall through the paint. (Post again if you want to know why latexes/acrylics can do this.)

I'm thinking the problem may be warm moist air escaping into your exterior walls during the winter to form frost. When that frost melts in sprink, it may be causing your cedar siding to get wet, thus causing the splits in your boards. The solution MAY be to simply use some sort of foam gasket or whatever around switches and duplex electrical receptacles in your exterior walls.


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## slickshift (Aug 25, 2005)

Wisco said:


> What is the most permanent way to address these problems besides replacing the boards


40/50 year or Lifetime siliconized acrylic (paintable) caulk


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## Wisco (Jun 18, 2008)

Thanks nestor and slick. nestor You are right you are a genius actually as I have read you threads. The boards should have been backstained and end stained when applied I was told when I researched this and bought the house, as some cupping occured and I had a sizable amount of the boards replaced in the offer to but the house. Ya I would be interested why latex's are like goretex? 

Slick pretty shrp ypurself...are ya sure the caulk will stay put with the flexing and moving of this wood? The previous owner used some typwe of caulk, you are right many variables, and it was peeling, flaking out like Bret Favre at a news conference.Sometimes the nails are 1/2 inch out from the wood I imagine this is movement? i did use cedar nails and did not nail thru both boards.

Think Urethane Glue is a dumb idea? Wisco


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## Wisco (Jun 18, 2008)

Oh ya sorry for all the typos, now I see spell check!


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