Yeah, drying wood in the sun in one big reason for warping.
Big box stores sell you wet wood - when you have it on the construction site it'll start warping and checking as it gets exposed to sun
Big box stores sell you wet wood - when you have it on the construction site it'll start warping and checking as it gets exposed to sun
For indoor structural construction, they're selling "kiln dried, 19% or below" Southern-Yellow-Pine or Spruce-Pine-Fir categories, specified in #2 quality grade or better. This SYP KD19 #2BTR mark or SPF KD19 #2BTR mark is lumber-industry-standard. It's stamped on the wood.
For outdoor construction like decks, they'll sell you copper-compound pressure treated wood which is indeed rather wet, and dyed green.
And then in a tiny section at the back, they'll sell you a single, large doug fir board green, as well as two SKUs of engineered LVL boards for bearing beams. Mostly you see Doug Fir more on the West Coast.
You can tell green / wet / fresh wood with a moisture meter, but you can also just pick it up - it will be up to four times as heavy.
KD19 is a maximum rating for structural uses. In reality they're often taking it significantly further than that in the kiln depending on the distributor (10%, 12%), but not quite as dry as the indoor of a house either. Drying distortion with KD19 is nonzero, but usually something small enough that you can ignore it with typical construction techniques. Large 2x12 SYP boards generate the most complaints, because the wood likes to warp more than others, and 2x12 is so large you're not going to get it sawn with a clean grain pattern.
How do you prepare those after buying before building?