Walked into a lumber yard near St. Paul last month and realized I've been ordering wrong for 6 years

I always spec #2 SPF for everything because that's what the big suppliers push. This old timer at Ward's Lumber looked at my order and asked why I wasn't using Douglas Fir for the headers on a 3 story walkup. Told me #2 SPF has more knots than a 90s boy band and I'd get better spans with DF at the same price point. He ran the numbers on a napkin. Saved me $400 and a lot of callbacks. How often do you guys actually visit local yards instead of calling the same big box supplier every time?

3 comments

3 Comments

beth27611h ago

Oh man, that napkin math is the real deal, isn't it? So here's my question: did that old timer also mention anything about the moisture content difference? I've heard SPF can twist like a pretzel if it's not dry enough, but DF stays put even when it's humid out. I'm wondering if that's why the big box guys push SPF so hard (maybe they just can't stock enough DF to keep up with demand). What did he say about that part of it, or was it strictly about the spans?

samflores3h ago

My lumber yard guy told me straight up that DF dries to a more stable moisture content because it's a tighter grain, so it doesn't soak up humidity as fast as SPF does. That's why you'll see DF hold its shape in a damp garage while SPF starts twisting after a few rainy weeks, it's the same reason concrete cracks but asphalt flexes I guess, just a matter of how the material handles the weather. He said big box stores push SPF because they can get it cheaper and faster, and the average homeowner doesn't notice the twist until after they've already built a deck and it's too late. Does anyone else see that kind of trade off in other materials they use, like how pressure treated lumber warps way worse than cedar if you don't sticker it right?

kaigibson18h ago

Use Douglas Fir because those old timers already did the math on napkins before you were born.