Whether to Finish the Undersides of Upper Cabinets

Cabinetmakers discuss whether cabinet undersides should be finished. November 30, 2009

Do most of you veneer and finish the underside of your wood upper cabinets the same as the doors? We do this and it is very time consuming, I have seen other cabinets that are prefinished birch underneath regardless of the finish on the doors. Just was curious what the norm was out there for the underside of uppers.

Forum Responses
(Cabinetmaking Forum)
From contributor K:
Yes. It's one more thing to set you apart from the competition. Just use 1/4 matching ply and it doesn't take more than an hour or so to do a set of cabs. I love saying to customers - "and we are focused on the details, after your kitchen is done and you invite your friends over for a cup of tea, you won't have to worry about the looking underneath your cabs (and they will) and saying ďwhat, did you run out of moneyĒ because your cabinets are finished like the fine furniture they are." This is especially the case if you are installing undermount lighting. How cheesy to look underneath at the lights and see unfinished material - yuck. Any picture you see of undercabinet lighting has finished undersides, so the expectation might already be there anyway. If you make your cabs larger (one 60" cab that looks like two 30" cabs) you can do one piece underneath saving time and effort, and only one cab to install, level and plumb.

From contributor F:
I used to leave them unfinished, same as just about all the large manufacturers do. Until the first time a client actually asked me about it. Once I actually thought about it I decided it should be finished, why not? So now if I'm spraying the boxes I'll spray the tops and bottoms. Otherwise I add a 1/4" panel after they're installed.

From contributor Z:
I always finish.

From the original questioner:
To contributor F: how do you "apply" a 1/4" panel after installation? Is this in the case when a light valance is present?

From contributor R:
We do the 1/4" applied skin as well. It makes for a nice clean look below. We oversize these and scribe to fit. I've never built a cabinet without a light rail, so that's never been an issue. We've even done them with blocking behind the skin for an u/cab lighting wire chase, with cut outs for puck lights - pretty slick look with no visible wires.

From contributor F:
As contributor R said, there's always a light rail of some kind on the upper cabinets. The light rail hides the front edge for a nice and clean look. I haven't tried the blocking before but I like the idea!

From contributor K:
I almost always finish the bottoms of the wall cabinets. I use two sided material the same as an exposed end. We finish everything in the flat before assembly.

From the original questioner:
To contributor K: are you cutting pieces with a CNC or panel saw, or are you old fashion with table saw? I was told the only way to spray parts prior to assembly is if parts are cut perfectly square with panel saw or CNC.

From contributor K:
I cut my parts on a CNC but that has nothing to do with the parts being square.
They need to be square no matter what. What difference does it make spraying them first if they are not square?

From contributor H:
Good question. I was wondering what you would do for a laminate cabinet. Keep it white MCP or laminate is like the finished sides?

From contributor J:
To contributor H: we leave the bottom white unless specifically called out for, or asked for by the customer. The white bottom is not noticeable behind the light rail. We let the customer know this up front, and it has never been an issue or concern.

From contributor D:
Finished for sure - matching color, or clear, (natural) thatís the dealerís choice.

From contributor W:
We spray our wall cabs upside down and backs and shelves separately - finished bottoms always.

From contributor O:
Furniture grade - usually. Kitchen cabinets - never.

From contributor P:
I finish tops and bottoms. It doesnít look complete when unfinished and what does that say about you and your work? If itís all about the money, sure donít finish and rationalize. But if youíre making the product, then thatís you out there.

From contributor L:
We do commercial only and always finish the bottoms of the uppers. Bottoms and finished ends are cut from pre-lam sheets, CNC and banded with matching 1mm banding. In some cases the tops will get done the same due to being seen from balconies. Doweled and case clamped.

From contributor X:
After the uppers are installed we nail matching finished 1/4'' panels to the bottoms of the uppers. After that we go back with a special piece of molding I have made (kind of like a fancy outside corner piece) that covers up the edge of the 1/4" panels. By doing this it also hides the bottom mounting screws. My customers really like it and this system has sold me lots of jobs. Sometimes it's amazing how such little things can impress some people.

From contributor G:
I always finish the underside of all upper cabinets I build. When re-facing I always give the customer the option of re-facing the underside (with the recommendation of doing them) it just looks more professional. Some choose not to based on saving a few bucks.

From contributor I:
We use 3/4" as species plywood for the bottom and they are always finished. I agree with the majority - it looks cheap if you don't. But why have an extra step of 1/4"? Use 3/4 and save the time, the cost is not that much more and it is a stronger box.

From contributor B:
Matching face if stained or painted or laminate with color match PVC edges if laminate cabs. Always.

From contributor T:
Interesting. The overwhelming majority in this thread use/add exterior materials for exposed upper bottoms. For me "unfinished" bottom usually means 19mm prefinished maple ply. (I'm presuming "unfinished" is a misnomer because everything's finished). This must be a regional thing because around here the overwhelming majority don't, whether tract houses or mansions. The majority I talk to around the country don't either. Don't know what that says. When I first started building cabinets there was an old timer that still used lumber for his backs. I recon he felt cabinets were "half assed" with ply backs. Methods change with time and reasoning. Pablo, it IS about money too. I don't build cabinets out of the kindness of my heart.

From contributor H:
I agree with contributor O. It is about the money when selling a job. You can't just give time and materials away. We do allot of commercial casework and unless specified we use white as a finished bottom for our uppers. That's a standard price. When we need to finish a bottom we use the prelam panel and edgeband the side. When I first worked for this one place they would belt sand the bottoms and custom laminate them. What a huge waste of time, especially when they had an edgebander. Time is money so no matter if you finish or not make sure you charge accordingly.