Cabinet Bottom Details for Recessed Under-Cabinet Lights

Ideas for building cabinet bottoms that will conveniently accept "puck lights." March 1, 2006

Does anyone have a good way to put a false bottom on upper cabinets for puck lights? I've used 1/4" plywood before, fitted inside the bottom of cabinet, and screwed to spacers so it would be flush to sides and face frame, but this takes a lot of time.

Forum Responses
(Cabinetmaking Forum)
From contributor R:
A good, inexpensive, and fast way are not always the same thing. I have been using a 1/4" bottom on upper cabinets for 18 years and have never been able to streamline the process much.

The first customer I did this for wanted every transition from face frame/end panel corners to toe kick/end panel joints to be mitered together so he didn't have to see any end grain or lap joints. The 1/4" bottoms were even mitered into the end panels and face frames. Talk about time consuming! I immediately fell in love with the look, but it was too tedious to build. I eventually moved to eliminate the miter joints on the bottoms and decided to rabbet them in to the end panels and face frames by cutting the rabbet after applying the face frame to the carcass. This is still the way I build uppers today. I have my Cabnetware programmed to leave the wall end short in height the thickness of the 1/4" ply and everything then falls into place ready for the rabbet. I attach a piece of scrap as a filler under and along the back edge of the bottom fixed shelf to support that edge of the 1/4" ply. This leaves a 1/2" air space for the fixture to fit into.

From contributor H:
I hang my doors lower than the cabinet box (euro) and apply a strip of material usually 4" wide with the light holes drilled. No false bottom, no changes to construction, concealed behind the doors, and can be removed at a later date for service.

From contributor M:
I do things the time consuming way, but it looks nice, too. The bottom of the cabinets are actually two pieces of 3/4" sandwiched together to make 1-1/2" thick. I drill my 2-3/8" hole for the puck light in the bottom piece and then route a dado through the top piece. I then chase the wires through my dado and out the back. That way there are no wires showing on the inside of the cabinet or underneath. I use the Hera lighting that has the heat shield plate to keep it from getting too hot.

From contributor T:
As mentioned, you want to pay attention to heat dissipation. Different fixtures have different requirements, so what you did last time might not work next time. We have the electrician furnish us with a sample fixture for fitting purposes. We do not, however, provide the fixture itself. If it can catch fire, you must assume that it will (think tall cookbooks sandwiched between counter and light fixture). If it does catch fire, you probably have an unprotected liability.

From the original questioner:
I'm not installing the lights, just a false bottom for the electrician. Thought I would put 1/4" ply on bottom of cabinets and cover the front and sides that show with small L shaped trim.

From contributor M:
My opinion is that using 1/4" for the bottom is kind of cheap looking. If I want something to turn out the way it should, I need to spend the time to make it right. Chances are, especially when doing corner cabinets, it's not very likely that it will look clean to apply a piece of 1/4" after the fact. If it does, a decent amount of labor went into it.

From contributor B:
Hera makes puck lights that require only a 1/2" or 5/8" recess, so you can put them in a single 3/4" bottom panel. I imagine you have to bore a horizontal hole in the panel to chase the wires. I saw these in a Poggen Pohl kitchen, and they do warm up that bottom panel.

From contributor M:
I use the Premium lights, which are pretty pricey. The drawback is that the bottom of the cabinet inside does get a little warm. But hey, it makes a great plate warmer! Ha, ha. In all seriousness, I did it on a kitchen three years ago and have heard no complaints at all.

Contributor B, if you look under the cabinet without the light in, you'll see the obvious hole for the light, and also the dado where the wires are chased from cabinet to cabinet and out the back of one of them. I fully recess the lights so it only sticks out like 1/4".

From contributor R:
Contributor M, I have to disagree with you about the 1/4" bottoms looking cheap. You must have seen a poor job done by someone. I adopted the process of finished bottoms for two reasons. First, it made possible a cleaner assembly for under cab lighting, but most of all, the customers and I fell in love with how clean and finished it made the underside of the cabinets. Even more so, when all a customer can relate to is the crappy look of box cabinets on their bottoms and tops that typically show the exposed end grain, or lack thereof, of the particleboard end panels. When done right, the use of finished bottoms can't help but make a good cabinet job look great. I'm not supporting "after the fact" bottoms, but rather the "built-in and rabbeted in and glued and sanded before finishing" kind of bottoms.

From contributor M:
I envisioned someone putting 1/4" bottoms on after they've been installed. I can appreciate the desired look with building the 1/4" bottoms in, but is there any concern for the strength of the material holding the light and fastening issues with the light to the wood?

From contributor R:
The 1/4" ply is extremely rigid when glued on all four sides in this kind of application and the lights are very light in weight. No problems with weight that I can see. I usually leave some vent holes in the back filler strip to aid the fixture to vent heat out. Never had a callback for these kind of fixtures.