"weights of 33 lb or similar."

It's probably, per bracket.

A wood countertop of that amount of overhang doesn't need support underneath if it's well fastened to the cabinets and those are in turn well fastened to the floor. First off, it's not as heavy as stone. Second, it has some flex, which stone does not. If someone leans on a similar unsupported stone counter, because it doesn't flex, it breaks. Wood would have to have a couple of linemen sitting on the overhang before you'd start to have an issue.

hollysprings is again quite correct.

I can't imagine how a counter manufacturer could state the maximum allowable load on a counter without knowing the size of the overhang, the direction of the laminated wood strips and the location of the load. Is the load in lbs per sq.ft. uniformly distributed or a single point load located at any one point? Where did you see this information?

I would not use a bracket at the middle of a 12" overhang but I might support the corners depending on the material and it's orientation.

Here is a link that might be useful: counter supports

This post was edited by Renovator8 on Tue, Jan 7, 14 at 16:54