I finally figured out how to keep those big slab doors from warping

About three years ago, I built a set of kitchen cabinets for a client in Asheville, and the doors were made from 30 inch wide cherry slabs. Within six months, two of them had a serious cup to them, maybe a quarter inch at the worst spot. I was sure I had sealed them well, but it kept bugging me. Last month, I was talking to an old timer at a lumber yard and he asked one simple question: 'Did you seal the end grain on the back side of the door, too?' I hadn't. I only sealed the faces and edges you could see. He said moisture gets in and out mostly through the end grain on the back, and if it's not sealed, it dries unevenly and pulls the door out of shape. I tried it on a recent job, sealing every single surface before assembly, and so far, so good. Has anyone else had a door warp even when you thought you did everything right?

3 comments

3 Comments

karenf401mo ago

Oh, that's a great point. I always seal the back edges, but I also make sure to let the sealed slabs sit in the shop for a few days before I even cut the joinery. It lets any last bit of movement happen before it's locked into a frame.

rodriguez.cora4d ago

My buddy Mark in Vermont built a beautiful walnut table top last June, sealed it up, and let it sit in his shop for a week. He was sure it was stable. Come October when the heat turned on, that thing developed a half-inch gap right down the middle... he had to redo the whole breadboard end setup. Just goes to show a few days isn't always enough if the seasons are about to flip.

stella2791mo ago

That waiting period is smart. Makes me wonder about the shop itself though. My old garage had wild swings in humidity before I got it sorted. A slab that sits stable in a damp spring week might still move like crazy when the heat kicks on in a dry winter. Maybe the real test is giving it time across a big weather change.