# Pressure Treated wood shrinkage



## Daniel Holzman (Mar 10, 2009)

How much shrinkage depends on the moisture content of the wood when you bought it, and the normal moisture content of wood in your area after it dries. As a point of reference, hardwood typically shrinks about 2 - 5 percent going from wet to dry, with most of the shrinkage across the grain, and only a small amount lengthwise. You can get a better idea of normal shrinkage from this website http://www.popularwoodworking.com/tricks/how-to-calculate-wood-shrinkage-and-expansion

Unfortunately PT lumber is often very wet, up to 50% moisture content, so the shrinkage can be well beyond normal tables. Unless you have a moisture meter, you are not going to be able to tell how wet your boards are. If you do know, you can use the actual moisture content in the website I linked to calculate the actual shrinkage.


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## SeniorSitizen (Sep 10, 2012)

I don't have a moisture meter but I prefer the method in this link as I feel it's more accurate as it gets right down to bones, even using smaller samples than recommended.

http://www.deldot.gov/information/pubs_forms/manuals/mat_research/pdfs/doh_2.pdf


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## gma2rjc (Nov 21, 2008)

I was told that 'local' lumber yards have kiln-dried PT lumber that doesn't shrink. Not sure if that's true anymore, but maybe you could check into it if you have a local lumber yard.


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