I've had that issue as well, but just kept dealing with it instead of replacing them. However, i'd recently had my fill of it, and decided to pick up a couple different size pans at TJ Maxx/Marshall's. I Chose the Cuisinart pans, which were thick with a non-stick coating. I've had no issues with warping, and that's at some pretty high oven temps. They were $8 and $10 for 15" and 17" pans. Well worth it, and i should have done it a lot earlier.

Thanks for this post - I've had the same problem and just assumed that I was a crappy baker.

I have Calphalon baking sheets--and they buckle.

i have some Chicago Metallic commercial pans and they dont buckle. but they're pretty heavy, so i suspect that's why.

they're not that $$ considering i've had them for years longer than the thinner versions.

Chicago Metallic makes great baking sheets and you can get them on Amazon. I got mine after I got tired of my previous baking pans, which would always buckle. My Chicago Metallic sheet pans have never warped even slightly, and my cookies come out much better than before.

I have those norpro heavy gage aluminum pans from amazon and they stand up very well to 500°F and don't suffer the buckling issues from the thermal expansion of the cheaper nonstick sheet pans I have.

I have a Calphalon sheet as well that has buckled, but I have a cheaper thick tray as well as a thin round pizza pan that are perfectly fine.

Yep, here's another person chiming in that my Calphalon sheet pans have buckled...

It's..... SCIENCE! :)

Pans can also buckle from being put under cold or tepid water when the pan is still hot... it breaks down the metal and will cause the buckling when going from hot to cold in the future.

I've had buckling problems with every metal sheet pan I've ever had, so I switched to stoneware pans.

The only thing they don't work for is Christmas cookies, when I'm making multiple batches, because they stay hot. So, once a year I buy a few disposables - I use them for the cookies and then they live out the rest of their days as oven liners.

Is it bad if they buckle?

I have two of the restaurant-style half sheet pans which I love. Unfortunately I used one as a steam pan for some bread I was making, and when I poured the water in (even boiling water from the electric tea kettle), the pan warped. So annoying! I will replace that pan and NOT use them for steam pans again. If you aren't stupid like me and you don't pour water into a pan that has already been heated up, you should be fine with a nice heavy-duty pan.

Btw, now I just spritz the oven with water when I put the breads in. The whole "steam pan" thing is overrated and fussy!

I have the Chicago Metallic sheets mentioned above, and my smaller one buckles and the larger one doesn't.

What's bad about buckling?...

I have a couple 13-guage half sheet pans made by Lincoln, which were the winners Cook's Illustrated sheet pan test. They're a little more expensive than most (about $18 each with shipping), but they're really thick (most "heavy" pans are only 18 guage), don't buckle, have an open bead that doesn't hold water, and clean up flawlessly. All in all a worthwhile purchase.

I got mine here: http://www.katom.com/054-5314.html

Gary - for most things it's just annoying. If you're baking an over full pie or some small tarts sitting directly on the cookie sheet it can cause a mess.

@sillyputty: i'm interested in the stoneware pans. don't they weigh a ton? do you just mean baking stones? where did you get them?

I have heavy William Sonoma pans and they do the same thing, but it's never caused any issues for me.

I have a few cheap baking pans from Target that work well - they're on the thin side. However, my thicker, slightly more expensive baking sheet from IKEA will warp as it gets used to the oven temp but it goes back to normal before I take it out.

I'm with a few above posters, what's wrong w buckling? Is it just that your pans are being misshapen permanently?

cookie sheets buckle due to uneven expansion of the metal. most cookie sheets today come with turned up edges on all 4 sides, and they are closed. so you have 5 surfaces that all expand with heat, but the bigger the area, the faster the expansion. the bottom being biggest of all is trying to expand in an area that is restricted by the folded up edges. so the bottom buckles as that is the only way it can expand enough. once the pan is completely hot, the buckling will go away. the pan has expanded uniformly.

there are basically 2 things you can do to counteract the buckling. one, as some people have said, is getting thicker pans, but this will alter the cooking slightly. the better alternative, (from my perspective anyway,) is to get pans that only have the folded edge on one side.

the cookie sheets I grew up with, and can't find any more, were simple stainless steel sheets with one edge bent up 90 degrees. very simple, and many of them could be stored in the place of one of the more modern 4 sided 'cookie' sheets. (actually jelly roll pans...)

circusboy-- single-sided doesn't necessarily work either. I have some of those "air" baking sheets that have a lip on just one of the longest sides. They are warped too. What brand do you buy?

I completely agree with AFeastOfSnacks. The Lincoln 13-gauge sheet pans are the best I've ever owned. Better than Chicago Metallic. Better than All-Clad. 100 times better than Calphalon. As usual, Cook's Illustrated was right again.

The buckling can cause problems with overfilled pies and such, as noted above... but the bigger issue for me is that it scares me to death. It's loud and rattles the entire oven rack it sits on.

Another Calphalon baking sheet user with the same problem. Scares the "sheet" out of me every time!

I cannot recommend the Lincoln pans enough. Worth every penny.

The only thing more annoying than a buckling pan is a
"rocking pot", or maybe a "seasick stove".

I have bought the nonstick Chicago Metallic and also the WS goldtouch cookie sheets (which I believe are Chicago Metallic as well) and they both buckled on me.

Yes, gourmandizzy, I second that! I got mine on CI recommendation, after I got tired of my Chicago Metallic jelly roll pans buckling like crazy. Lincoln pans are not that expensive if you can find a local restaurant supply store.

As far as why buckling is bad, for me it's because cookies baked on a buckled sheet brown unevenly and are wonky looking.

I have been able to find these pans at my local Sam's Club(Costco) for around the same price. I LOVE these pans and have seen them in use on the Food Network as well.

I use and love my pampered chef stone baking sheet. My mom swears by the "insulated" baking sheets because of the buckling reason, they have a double layer and air in between. We also think they bake more evenly too...

No disrespect for anyone's mom, but I have my doubts about those "insulated" sheets - they were supposed to prevent burned bottoms, right? I don't see them for sale much anymore, either, I wonder if they were a fad. I have one, AND it has only one edge at a 45 degree or so angle: still buckles. But I like the edgeless aspect because my Silpats lie flat.

For pies, I put the "drip" sheet on the oven rack below the pie.