When I built this rack, it was perfectly square, the saddles were all tight, and it didn’t move at all. 3 months later, I guess the pressure-treated wood has shrunk and it’s sagging.
So what’s the right way to build something like this? Just let the lumber sit for several months to dry out? Don’t buy from Home Depot? Is there a way to tell when the wood is “ready”?
There’s lot’s of people learning in this thread.
Untreated lumber will soak up water and swell, the dry in the sun and shrink. This process will allow natural twists to reassert themselves and stress and strain will warp into the wood.
Right, so how do you account for that in the design? In my photo, I didn’t account for it at all. The square cuts have changed and it’s failing. I can resolve it with braces as suggested, but now I’m wondering if those braces will change and it’ll go out of square again.
Not really. I’m no woodworker, but I think your main issue is that you only used one bolt in each joint. Usually they have two bolts or screws, placed diagonally, to prevent rotation even if the wood moves slightly.
If you really want to rely on the wood itself, you’ll probably need to do it timber-framing-style. But modern carpentry is perfectly fine if aesthetic isn’t your goal.
Or in the case OP, they bought pressure treated wood which is literally injected with moisture (chemicals) to prevent decay. If you ever picked up a piece of fresh PT lumber it is HEAVY from all the moisture. Best to let it dry a couple weeks before working with it.