Granite countertop overhang support [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile

PDA

View Full Version : Granite countertop overhang support


dk2surf
08-11-2004, 08:11 AM
My question is we are having granite installed on a peninsula that is atop
a kitchen cabinet, 48"x24" and will have a 14 1/2" overhang which will span the cabinet (48").

We have 5/8" plywood installed on the countertop to support the granite
slab, but need to reinforce it. Corbels and/or a post will not work as there are cabinet doors underneath. We thought of using a 1/4" steel plate then 3/8" plywood, would that be enough support. Do you have any suggestions? Are there any rule of thumb as to x amount of support for x amount of overhang.

Sponsored Links


Mike2
08-11-2004, 09:26 AM
Good morning surfer. How about a first name we can call you?

Just want to make sure we understand what you have there before getting into suggestions. Peninsula base cabinet is 48" X 24" with 14 1/2" overhang, so will the granite slab CT be approx. a.) 62 1/2" X 24"?; or b.) 48" X 38 1/2"?

bbcamp
08-11-2004, 09:37 AM
First things first. I don't think you've planned for enough plywood under your granite. 3/4" thick plywood is the minimum for ceramic tile, and stone needs about twice that, 1-1/4". So, for starters, you need to double your plywood.

Second, the usual rule is that overhangs less than 10 inches don't need support, if they have the proper thickness plywood (see above) and it is well supported by the cabinet. So, a 14-1/2" overhang means you need some support.

1/4" steel plate is about 63% as stiff as a 3/4" sheet of plywood, so your 5/8 plywood plus 1/4" steel plate equates to about 1-3/32" plywood. That's not going to work. You will need some steel framing, like (and I'm guessing here) 1" x1" x 3/16" angle iron.

Let's try another approach. Suppose we use the double 5/8" plywood base, support the first 24 inches by the cabinet, and about 3 inches in from the edge, we place a skirt (a 1x2) that is supported by the wall or other cabinets and the free end by a leg to the floor. The skirt is reinforced by a 1-1/2 x 1 x 3/16" angle iron so it can span the 48 inches. You now only have one leg in the way, but your granite is happy. :D

I am curious, though. Since this is a peninsula, and (I'm assuming) that the long side is clear on front and back, and the overhang in on the front, why not put the cabinet doors on the back. The cabinet will be easier to access without the overhang over the doors.

bbcamp
08-11-2004, 09:39 AM
Just want to make sure we understand what you have there before getting into suggestions. Peninsula base cabinet is 48" X 24" with 14 1/2" overhang, so will the granite slab CT be approx. a.) 62 1/2" X 24"?; or b.) 48" X 38 1/2"?


Well, yeah, Mike. Get clarification first! Heck, anybody can solve a problem that way! :D

dk2surf
08-11-2004, 12:01 PM
Hi Bob,
The answer to your question is b.) 48" X 38 1/2"?

Surfer Girl (AKA Dawn)

bbcamp
08-11-2004, 01:24 PM
OK, Dawn. That's what I assumed. Check out my first post.

Mike2
08-11-2004, 01:28 PM
You're a lot better guesser than I am Bob....I need all the help I can get.