Continuous Cabinet Bottoms for Upper Cabs

Thoughts on the structural integrity of alternative cabinet construction configurations. July 29, 2012

I have learned traditionally that when constructing a cabinet the sides run through the top and the bottom, making the top/bottom span between the sides. I am fine with that construction I have been doing it this way for over 20 years. We are looking at saving a step when we have a bottom of an upper cabinet finished. If we are going to have a white bottom (melamine) are there any unforeseen issues in running the top and bottom through and stopping the sides at the top and the bottom. Is this poor quality?

Forum Responses
(Cabinetmaking Forum)
From contributor L:
It would seem like the fastening would be going the wrong way if the bottom was covering the sides. If this is FF it might work. FF glued to front edge of bottom and a ledger on the back edge. Not a good idea with frameless.

From contributor S:
I think it would look fine. My concern would be strength if the bottom of the cabinet is full of heavy items. The weight would be forcing the bottom straight down and away from the gable. What kind of fasteners were you thinking of using? We just edgeband the ends of the gables for our uppers.

From contributor K:
My bottoms sit in rabbets and my tops sit in datos. We edgeband the bottoms of our gables as well. Glue in the rabbets and datos with screws and captured backs is plenty strong. We use 3/4" prefinished ply with 1/2" backs.

From contributor S:
We have done this many times. I have files set up in CV for reverse construction. Sometimes for runs of upper cabinets that are higher on the wall it looks better not to have all edge-banded panels showing and as you say it may save a step on finishing. We have done this sometimes on base cabinets also but not as often. It also makes the ends the same as vertical partitions. Our usual construction method has all the ends and partitions hanging from a notch and rail system so joint strength is less critical.

From contributor A:
I laminate the bottoms with white cabinet liner. This doesn't save a step but it's a cleaner look. I also use anodized aluminum t-molding for edge banding on all contemporary cabinets.

From contributor J:
The bottoms don't hold that much weight. All the weight is on the back of the cab. Go with 1/2 backs with dados. You can only fit so much on a bottom shelf.

From contributor O:
We did a library where we had to use one inch solid for the shelves, because of the weight. Had they just been upper cabinets the bottoms would have pulled right out with this type of construction. I think we just have to use common sense, find out the application for the unit, and build accordingly.