Are you sure that the lumber was warped at the lumberyard? Or was it OK then, but maybe it warped after you installed it. Sounds like you have no decking nailed or screwed. Maybe these boards, exposed to the sun, and nothing to keep them from warping, did what PT likes to do. They warped.

If your crowns are facing up, I think that is OK. The weight of the deck will tend to push it down. You can also shim joists to get them flat and even before installing decking.

What kind of "decorative" lumber is the pergola going to be built out of?

"Mom and Pop" may not be that bad. Don't be so sure.

Yes, we did nail down some decking boards and that's when we noticed it. It threw everything off. We took it out and turned it upside down and it was ok. So it just had a crown to it.

When I speak of decorative lumber, I'm talking about the boards that run across the top of the pergola that stand on end and you cut the ends of them scalloped. How bad is that going to look if those boards are all warped and bowed? How can you guard against that really?

Time between purchasing the lumber and nailing it in place may have been 2 hours. So not enough time for it to warp or bow. We bought it that way.

You bought it that way....Man this deal is on you.

Two hours in the sun is more than enough time for pt lumber to through a fit.

All of us fight the nature of pt pine exposed to the sun. There are several little tricks to building with it but dont think your the first or the last to have it happen.

J.

John's the pro. Listen to him

Other comments - avoid nails, if the PT is given a chance to warp, it won't even notice them. When in doubt, use screws and construction adhesive. Large pieces (beams), through bolt 'em.

Keep your loose PT out of the sun (under a tarp, etc), while you work.

Here's a pergola I built, all PT. Everything is screwed in two directions. It didn't warped.

{{!gwi}}

I buy alot of my PT lumber at Lowes, and it's wet. I make sure to pick out good boards, but I notice cupping and warping by the time I get to the jobsite. I can deal with it when building a deck substructure, but that crap isn't good enough to use where it's gonna be visible. When building pergolas, I always go with cedar or Ipe.

As John mon said...we have tricks that enable us to work with PT..."always set the crown up" is one of them.

steve

I would love to hear any of these tips. I am looking at having a load of lumber delivered this week for my frame and being a weekend warrior much of it will not get installed right away, but over the span of a couple of weekends. Am I in for a nightmare letting the wood sit that long? I guess at a minimum I should cover it with a tarp. Would I be better off storing in my crawl space until I need pieces?

Riles

Pressure treated lumber can be a royal PITA because the high moisture content causes all kind of weird stuff to happen. As John mentioned a couple of hours in the sun is enough to turn it into a pretzel. The best solution is to hand pick the lumber although I've sent really bad stuff back that's been picked by the lumberyard.

There is "re-dried" PT lumber and that eliminates some of the problems but it's harder to find and more expensive.

Nice looking little thing Tom, I like it!!

Guys pt lumber is a deal,,,,,the # 1 grade usually has fewer knots and its kd twice one time before going into the retort one time after but its still pt pine and will do the same thing left alone exposed to the sun.

The real trick is get it installed in a timley nature,real timley. After its out of the sun with a secure fasten everythings fine. Riles Mon a tarp will do just fine make sure the material is stacked up in a military way.

Do not expect 20' long material to behave with no care at all of any kind ghesssssssssss like Ka Da!!!

One thing I do with pt 4x4s installed in the frame,we cut the decking around them so while this takes place the posts are at risk so I cover them with white fiber trash bags until its time to wrap them. John Mon

Not sure where all this warped lumber is coming from. I do have some issues every once in awhile with 2x10's for joists delivered. But the ones I did install never have warped like described after installation. Sometimes I've built decks and wasn't able to install decking for days, due to weather. Never had an issue with warping. This is in the Southeast.

John Mon -

Thanks for nice words.

Folks complaining about the unruly PT. Look what I have to deal with!

I almost got between mama bear and her four babies putting that PT together

{{!gwi}}

{{!gwi}}

That cant be good!!! Im glad her mood was in an upswing.

J.