What to do about warping boards on pergola?

Question

the top beams of my new pergola have warped. The boards are 14` 2x4`s (treated). Should this have happened? What should I get to replace them? Any input at this point is truely appreciated. thanks.

Answer 1

you need to replace them,pressure treated lumber wants to warped bad,you might use redwood or cider they last as long but a little pricier,good luck

Answer 2

most long legth treated 2x4's will warp, as would 2x6 or 2x8.  try using cedar or fir and treat the structure with a weather or good stain after completion.  but for that length i would have used 2x10's, but this can get pricey.  

if you choose to use a smaller dimensional lumber, install a layer of 2x2's along the top of them, it adds a unique square grill look and will also keep the boards straiter.

another look i have seen is installing 1" or greater wood rod in between the crown joist, again this will hold them in place and add a unique design.