Should I Finish Cabinet Backs and Drawer Bottoms?

even the ones that don't show. December 28, 2007

The topic of discussion in our shop is putting a finish on every part of cabinets. How many of you put finish on the outside of cabinet backs and underneath the cabinet itself?

Forum Responses
(Finishing Forum)
From contributor W:
Not many would be my guess.

From contributor G:
I do. A quick coat of finish for sealing is all.

From contributor P:
No and no.

From contributor J:
I do. It's pretty cheap insurance against warping and will help some with moisture and movement.

From contributor P:
I'll paint the bottoms of bath vanities and also the sides of boxes next to dishwashers. One coat of Kilz primer and one of whatever brownish paint I can find on the "oops" table at the paint store. I don't know that it's necessary to paint the bottoms of the vanities, but it only takes a few minutes.

From contributor H:
We always do the bottoms and tops of our uppers.

From contributor A:
If you can't see it, why finish it? We are talking about unexposed cabinet bulkheads, correct? I've seen some people actually spray finish in a box that is all drawers. You can't see the inside unless you take the drawers out. The underside of uppers is usually a good idea, but I don't go nuts trying to putty every defect.

From contributor L:
Everything gets coated. Backs of backs, bottom of the cabinet on lowers, and tops on uppers. To insure everything has the smallest amount of movement and is sealed properly, this is what you need to do. I do only higher end cabinet work. If you are doing low end work and small dollar cabinets, this is a way to save on money, product and time.

From contributor R:
I spray everything inside and out. Backs and unseen areas get a coat of black vinyl sealer, insides of drawer boxes get finished just like the cabinets, just don't get all the sanding attention. I even spray the bottoms of cabinets. It takes very little time, I do it before sanding the casework so no masking is required, and I find my cabinets get a lot more respect during installation from installers without all the nasty stain rag marks, etc. The customer is impressed because they are usually there for at least some of the installation, and if there ever is a problem with moisture or wood movement, the black sealer makes it obvious that it was properly sealed. Trust me, if it ain't sealed and there is a problem, it will be your fault, whether it is or not. Cheap insurance.

From the original questioner:
I spray a light finish on the inside of cabinets with drawers, but don't sand, and always do the tops and bottoms of cabinets, finishing the bottoms as I do the rest of the cabinet as it shows, but what I wasn't doing was the outside of the backs and the bottom (underneath) of vanities. My husband wants everything covered, so I thought I'd get some feedback from you all. Thanks for the responses.

From contributor A:
A better question is why are you not using pre-finished plywood for at least the lowers?

From contributor D:
We seal all surfaces, including the bottoms and outside backs of all our cabinet and furniture work. All wood products react to environmental changes, and unseen parts are not magically exempted from this maxim.

Public relations is part of what we all (should) do. There is something we call "the first 15 minutes." Someone just spent 80k for a jumble of boxes and stuff, and when they see it, if there are unfinished parts and drips and runs, etc, it may make them question their investment, then look closer and wonder about this, or that, and then a whole host of problems - real or imagined - can arise before you know it.

However, if the boxes are neat and clean, wrapped and finished all around, no cute drawings, no crap, then the opposite occurs. They are reassured that their investment was wise and will look forward to the project's completion, and we have far fewer customer problems.

From contributor O:
I can see sealing the bottom deck on vanities, end panels near dishwashers... but there is no way you can convince me that it is time well spent to seal the inside of a drawer bank or back of a back unless the cabinets are in an extremely damp environment.

From contributor G:
What does it take, after all? A couple waves with a spray gun. Hardly a huge investment in time or material. I think that all surfaces, inside and out, should be sealed. That includes drawer bottoms.

From contributor Y:
It can be a huge investment in time and material depending on how many cabinets you produce.

From contributor D:
It can be an investment in your future to do the seal, in my opinion. By the way, cabinets will all experience wide changes in humidity in their lifetime. Flood, failed HVAC, remodeling, all the in-laws come to visit and shower 22 hours a day. Something's going to occur. It's okay if you don't finish or seal the backs or bottoms. This is exactly what helps us differentiate our expensive product line from the troops slugging it out in the trenches. Makes our job easier.