Replies

1. 
   GaryW | Feb 20, 2010 03:10pm | #1

   We prefer to use a piece of plate steel, 1/4 to 1/2-inch-thick, in place of or in combination with plywood, for overhang support.  The greater the overhang, the thicker the steel.  In the two attached photos, the smaller countertop with a 12" overhang, has a 1/4-inch plate under 1/2-inch plywood; and the larger countertop with a 16-inch overhang, has a 1/2-inch plate under 1/4-inch thick plywood.

   
1. 
   gofigure57 | Feb 21, 2010 08:26am | #2

   Nice work Gary

2. 
   GaryW | Feb 21, 2010 11:00pm | #3

   The plate size is based on it's overhang.  The 16-inch overhang overlays the cabinets and 4 1/2-in-thick wall behind it by about 20-inches or so (I don't remember), and it's both through bolted to the Euro style cabinet tops or screwed to the cabinet's vertical panels with 2-in-long confirmat screws.  The 12-inch overhanging top extends about 16-inches or so over the cabinets behind it.  Both were cut away around the sinks.  The steel is otherwise sized like our standard plywood "roughtop," which leaves room for the granite's 1 1/2-in-deep overhang beyond the roughtop edge.  A shop two doors from my own cuts, sands and delivers the steel to my job site and I drill and countersink the plate on site.

   The attached photo shows the back of a 12-in-overhanging bartop, which we used 1/2-inch steel under, and the steel had a piece of 1/4-inch steel welded to its back edge, extending vertically below the steel roughtop.  It's behind the granite back splash which is behind the sink faucet.  I can sit on the counter's overhang.

   
1. 
   woodworker52 | Feb 21, 2010 11:42pm | #4

   thanks for the info Gary. One day I hope to have a top like this in my own kitchen and now I know how to do it correctly.

   Dave

3. 
   GaryW | Feb 22, 2010 12:55pm | #5

   I've never seen cracking in a countertop we've installed, whether over corbels or a steel plate.

   Countertop surface height above the finish floor surface is 36-inches.  If the countertop's edge is 1 1/2-inches thick, then we use a 3/4-in-thick roughtop on top of our cabinet carcases, whose top is 34 1/2-inches above the floor.  The edge of the roughtop is hidden by the 3/4-in-thick turned stone edge.  If the countertop was 3/4-inch thick, then the cabinet carcase top would be 35 1/4-inches above the floor, and the roughtop, if needed, would be part of the cabinet, but over a dishwasher, there'd be a 3/4-in-thick plywood roughtop with a finished, exposed front edge.

   The bottom surface of the steel plate is usually visible under a countertop overhang, but we paint that - usually black.  If the customer wants a wood surface showing, then we take the extra time to laminate, with epoxy, a plywood surface to the bottom surface of the steel. 

4. 
   PSeverin | Feb 22, 2010 06:18pm | #6

   I have been told by granite suppliers that a granite counter tops can support itself with between 10 and 12" projection.   After that it requires some sort of support.   I can't see any reason why the steel you propose wouldn't be adequate if turned vertically.   But if you plan to lay it like a strap 3/8" high and 2" wide I would question if it will provide adequate support  for any great distance.   Engineers usually have us use steel tubes when cantilevering  which you might consider.  A 1 x 2" tube could end up being considerably stiffer than the member you've selected.   I believe a cantilever has 1/3 projection with 2/3 embedment. 

   Peter

    

1. 
   GaryW | Feb 23, 2010 10:31am | #7

   Yes it can support itself, but some have nearly invisible cracks that render it weak, so I believe good support is essential.  Knowing the overhang will support someone hoisting themself up to sit is my test.  No, it probably won't happen, but what if it does when my back is turned?

5. 
   amit420 | Nov 06, 2010 12:48am | #8

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