supporting a ceiling cabinet with MDF?

[James Baker SD]

We have had a couple of wall mounted ceiling cabinets either come off the wall or the cabinet itself disintegrated due to over loading them with heavy objects. The kitchen cabinet that disintegrated is sitting on the patio as scrap, beyond repair. My wife wants me to install vertical supports between the kitchen counter top and the under side of the surviving cabinets that contain our dishes (very heavy) and our glasses and cups (fairly heavy). I have ready finished MDF with perfectly matching laminate all ready on it (the disintegrated cabinet) that I could use to brace the other cabinets. I also have scraps of 3/4" baltic birch from the replacement cabinet I am building. I am thinking something about 12" deep, 15" tall and 3/4" thick under the other cabinets to give them extra support. My wife does not mind a mini wall sticking out from back to front as we store appliances there and the mini wall would not interfere with our use of the space.

Being lazy I would like to use the MDF as it already has laminate glued to it. Otherwise it is prabably destined for the garbage can. The cautious part of me wonders how well MDF withstands a compression load. Would the baltic birch ply be significantly stronger? In any case, is the MDF strong enough? Thanks.

James

[Jamie Buxton]

Structurally you'll be fine with a MDF&formica panel.

If you don't quite believe some random guy on the web, you could rig up a test. Rig a 2x8 so one end is standing flat on that 15"-tall panel, and the other end is tied so it can't move sideways. Now stand on the 2x8 above the panel. You probably weigh more than the dishes. If the panel doesn't collapse, you're home free. Or if you want to test it to higher loads, get your wife to join you on the 2x8. Heck, jump up and down.

[Sam Murdoch]

If you could make up some T braces - the back center leg being baltic (which you could paint to match the cabinetry somewhat closely) and the face being of the prefinished MDF I think those would be rugged enough. The MDF by itself - NO . Ideally dado the back of the MDF an 1/8" or so deep to fully receive the thickness of the baltic and secure all with glue - no screws needed. 2 legs like that would be quite strong but they need to support something real at the top. No good just to go to the bottom of a flimsy & already overloaded cabinet. Either provide a full width strong back or make certain that the upright supports are carrying the load directly under the side panels of the cabinet above. Alternatively you could just connect your 2 verticals together with a 6" to 8" wide stretcher. This should be securely fastened to the uprights. My concern is that the MDF will deform under the load without the braces at the back or as the stretcher. If I understand your question :)

Sam

[Zach Callum]

Why not take down the surviving uppers and do what is necessary to fix them?