Does Structural Lumber Warp?

applebuilder

Does moisture loss and shrinkage affect the structural integrity of a building? I'm talking on a small scale, say a shed 8'x12' and most likely using Douglas Fir. Is moisture content a consideration when building this size of a structure? Thank you.

Termite

High moisture content (wet use applications) plays a role in lumber's strength, but not in this case. Yes, structurally graded lumber will absolutely warp/twist/shrink/check. When selecting lumber it is best to look for KD Doug fir lumber that has been kiln-dried to a moisture content of 19% or less. That'll help it remain dimensionally stable. Honestly, the "green" undried stuff will work fine for building a shed. Doug fir is pretty stable in general compared to pine lumber, especially southern pine.

For an 8x12 shed the structural considerations are pretty minimal.

Willie T

I'm with KCT. Stay the heck away from SYP PT if you want to have any hope of your lumber remaining straight.

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Willie T

applebuilder

Thanks for the advice, good thing all we have around here is doug fir, no southern yellow pine to be found.