Hi,
I have an order for a custom cabinet which will support a 400lb slab of granite. Owners wants plenty of open sapce so little room for more than 3/4″ material. It’ll be about 96’x39″ with an 18″ overhang. I have several ideas that will work but don’t proclaim to know it all. This will be an installed kitchen island.
The basic design will be 32mm system, Blum hdw etc.. with full overlay. I’m thinking making the cabinets as components then tying them together securley a good start. It’ll be about 6 boxes of 34″ material thet will be about 34″x24″x18″ or smaller.
Any ideas appreciatted.
Notrix
Replies
Will you be using the Euro adjustable feet or conventional box-on-base? 400# should no big deal for the cases, though I would go with 3/4" sides & back vs. 5/8".
The overhang will need supplemental support. Best to work with the granite fabricator to get his input on how best to support the thing. He may suggest things like imbedded steel in the plywood top. There was a FHB article a few years back that had something like that.
Thanks,
It'll go on a box with lots of cross braces, almost a torsion box affair.The entire cabinet will be of 3/4" oak ply with a 5/8" subsurface for the granite. The 5/8" will be on top of a 3/4" sheet so 1 3/8" thick top.I was considering using some 2x4 lumber hidden inside, a frame work the individual boxes attach to but that will complicate design.N
No need for any additional bracing. The individual units, bolted or screwed together, give you 1 1/2" thick sides which give all the load-bearing support you need. Again, the fabricator is the best source to confirm the specs, both for the 5/8" support over the spans you will have plus the overhang support. Let us know how it turns out!
Excuse my butting in here but I would suggest that you talk to the suppliers about a continous substrate.My supplier does not like to install over a continous surface.He prefers strips .These are made of 3/4 ply glued and screwed to resemble angle irons.
I'd second all of the above answers. Additionally, you may want to use 2X material for the base/kick and then veneer it with 1/4" oak. A word about granite fabricators: Have the boxes finisned and installed before they recieve the order for the top. Sometimes they will make an error on the template and construct the top wrong, and granite is not like Corian or other solid surface material, it can't be resized easily.
My concern would be the 18" overhang. The fabricators that I used to work with when I had my cabinet shop required a steel frame attached to the top of the cabinet that extended past the cabinet to support the overhang. I also have to question a home owner who can't deal with loosing an additional 3/4"-1" for the needed cabinet/top support. These are the types of clients that usually give you nightmares before the job is done.
When I built frameless cabinets, I used a seperate 4 1/4" high toe kick that was preleveled and screwed to the back wall and if possible the floor. The cabinets were then set on top of the toe kick, screwed together, then slid up to the wall. The gaps between the cabinet back, and the wall were shimmed and then the cabinets were screwed(not nailed) to the wall. The front of the cabinet floor was screwed down to the top of the toe kick. I never had a stone, solid surface or tile top sag or crack because of the cabinet installation. I then used a 3/4" thick face of plywood or solid wood to skin the toe kicks. This was usually prefinished to match the doors. Cabinet sides, bottoms, top rails were 3/4" and the back was 1/4" with 3/4" nailers top and bottom of the back.
I also used laminate shims, and plywood shims for leveling my cabinets. Not wedges of particle board or cedar shims, not that the cedar shims are that bad, just my preference. I know a "high end" shop in SoCal. that uses a 30* wedge of particle board, shove it under the edge of the toe and brake it off. Four little chunks of partcle board to support a cabinet and granite top. What do you think happens if those pieces ever get wet?
I understand your concern about the overhang. But seeing how the top is going to be granite I would get the specs for supporting the top from the granite installer. And I would do it in writing.
If there is an issue with this stupid heavy/costly counter down the line I would want all the liability to be on the counter people. I've heard horror stories about these tops. The tops in question were cracking at inside corners where there was some normal shifting in the house walls.
You never know.
The weight of the granite should be no concern at all. Three guys at 135 pounds apiece weigh more than that. Have you ever built an island you'd be afraid to have three guys sit on?The main thing is that the substrate be flat. Whether it's continuous or in strips, all the contact points need to be in the same plane. And whatever you end up supporting the overhang with needs to be at least as stiff as the granite, so all the contact points stay in the same plane.
I agree. I haven't done any work with this material. The point I was trying to make was that the counter top people should be liable for any problems with the top. So all the ideas for supporting it on this forum may be valid but they weren't addressing the issue of separating yourself from the liability for the top. So communicating with the top installer about their specs in writing would go a long way toward doing that whether or not it was the right way technically. It was more of a business statement than a technical one.
Just my two cents.
I wasn't disagreeing. I should have replied to message #1 or changed the To: line to ALL. You're quite right.
Thanks again,the over hang will be 18" but the substraight will be 1 3/8" thick with gussets to support it. I may insist on legs at the out corners.The 5/8" is the thickness of the bullnose. That's set in stone (excuse the pun<G>) The distributor deals with 100's of these slabs and has recomended installers. I'll be on hand to build and supervise but I have made it cleasr I have no experience with granite.I will speak with the granite man to get what he'd say he'd guarantee, even though I doubt he will.Notrix
I just finished a kitchen install yesterday, and went over there today to be around when the granite guy came to make his templates.
These were very middle of the road cabs, so we went to some effort to shore up the bottoms with 2X stock, and assumed the granite people would want additional supports to transfer the weight of the top down to the floor.
BTW, this top is going to be 1" thick.
When I asked about strengthening the cabs, he just laughed, and said we had wasted our time. Claimed the top would do just fine, even with Ikea cabs, which structurally, are pretty flimsy.
He also said that 12" was the max overhang without additional support (for the 1" granite).
Design suggestion for the 18" overhang: Corbels. Lots of load-carrying capabilities. And use no floor space.
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