Cabinet Door Warping Problems

Job-site humidity can warp cabinet doors. To reduce problems, some would recommend avoiding Poplar in favor of Maple, or even MDF. October 27, 2011

I have done several inset door cabinet jobs in the last year or so. Now that it is spring, I am having a difficult time with the moisture content in my most common material (poplar). On most of my doors, I use the cope and stick/stile and rail 5 piece door method. When the job leaves the shop and is installed, the doors are perfectly spaced with 1/8" reveal. The cabinets may sit in a non-climate controlled house for up to 2 weeks before the painters get to it.

When we come back to adjust, about 1/4 of the doors are slightly warped. I can adjust the door out past the face frame to get the non-hinged side to close correctly, but then my hinged side is past the frame. Has anyone else out there had this problem? I use a concealed hinge, and unfortunately, my market does not allow me to use a Blum hinge. That said, side by side, the Blum and the knock off hinge have very similar adjustment capabilities. I know that the builder has some responsibility to get to the job in a timely manner, but I need to bypass the builder in some way to achieve less work for my company.

Has anyone ever installed their cabs, then pulled the doors, laid them on a flat surface at the job, and wrapped them in plastic to shield the door from humidity? Does that just create a greenhouse effect?

Forum Responses
(Cabinetmaking Forum)
From contributor J:
I think I'd try to work something out with the GC or the painters to either hold off the delivery or possibly prime the doors before they go out. Poplar can be difficult this time of year with the humidity. I realize the difference in cost, but soft maple might be another option for your doors. It seems more stable than the poplar this time of the year.

From contributor G:
I second the suggestion to switch to soft maple. I used poplar for paint grade passage doors for a while and had a lot more warping problems, so went back to soft maple.

From contributor E:

I agree with the previous posts; poplar seems to move more than soft maple and personally I find poplar to be a little light and soft for doors anyway, though just my opinion there.

Usually inset door cabinetry is at the top of the pricing spectrum. Why would you not be able to use the Blum hinges? Not saying you need them, but the difference in cost over a kitchen's worth of doors is pretty small.

If you have the ability you may also consider priming doors before they go out. It's not as good as a coat of paint, but it's better than going out bare.

From contributor A:
Start looking at the growth rings of the poplar. I have seen 5/16" ones. The weed grew 5/8" in diameter in one year! I faced a piece on the jointer and let it sit on the bench for 15 minutes. I came back and it was already cupped. As time goes on, poplar is going to get worse and worse. We are spraying too much CO2 on them. They are really growing like weeds. I likewise only use soft maple in cabinetry. Paints a hell of a lot better as well.

From contributor D:
For your paint grade work, you should seriously consider using MDF for your panels. It's much more stable, paints better, and you don't have to glue up, plane and sand your panels. I know a lot of guys equate MDF with lower quality, but in fact it is a better material for that application. I have never had a callback for an MDF paneled door, but I certainly have for solid wood panels that shrunk, expanded and blew out their frames, or just plain warped. Even on high end paint grade (I know, it's an oxymoron) I've never had a negative comment from a contractor or customer about using MDF for panels. Try it, you just might like it.

From contributor L:
I rarely use poplar for doors. Soft maple is the next low cost choice. It won't dent as easy, mills as nice as poplar, is a little tougher and the paint surface is better than poplar because it has a tighter grain pattern. If you insist on using poplar, you need to prime your cabinets, or at least your doors. Use something like Clawlock. It will seal pretty good. Or even vinyl sealer - you can put just about anything over both of them.

From contributor N:
Our natural hard maple and natural soft maple prices are about the same. Some soft is actually higher price than hard, thanks to supply and demand. Hard maple is a most excellent paint grade material.

From contributor E:
Depends on timing and location I guess. Last load of soft maple for me in the northeast was less than the cost of poplar. Also a little less than half the cost of hard maple at about $1 bd. ft. It's as cheap right now as I've ever seen it. I'd prefer using hard maple too. I find it machines a little easier, and also would be one less material to stock.

From contributor R:
I would state in my contract with the GC or homeowner that the primer cannot be waterbased (yet another reason for pre-priming before leaving the shop).