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RE: Support brackets for granite overhang? (Follow-Up #10)

posted by: stacywomble on 11.07.2011 at 10:59 pm in Kitchens Forum

Hopefully this will help future readers looking for answers. The post by Buehl is all over the conditions of needing support as recommended by the MIA (Marble Institute of America).
This is for "Single-Level" counters with cantilever overhang:
For 3cm stone: any overhang over 10" will need additional support; spaced every 36" or less.
For 2cm stone: any overhang over 6" will need additional support; spaced every 24" or less.
For "single-level", the goal is to support the cantilever. We do this with CONCEALED SUPPORT. Single-level concealed supports use the mass of the supported material to "reach out" and support the un-supported material.

"Raised Bar" support is of a completely different breed. Unlike "single-level" support, "raised bar" supports support the whole darn top. (Gosh, I need to write an article explaining all of this stuff!) There is a rule called the "2/3rds Rule" which says that in dealing with overhang, that 1/3rds overhang much be supported by 2/3rds of the width of the overhang. (Example: a 36" wide counter should have 24"(2/3rds) of support (cabinetry) with 12"(1/3rds) overhang.) Raised bars blow this rule out of the water so we have to look at it differently. ALL RAISED BAR COUNTERS NEED SUPPORT! We use "SB" support to support raised bar overhang up to 12" and "SBS" supports to support anything over 12" and up to 18" overhang. We Do Not recommend overhang over 18" on either "single-level" or "raised bar" counters.

Let me address Rodding. The process of grooving the bottom of the material and epoxying in steel rod is an acceptable practice in suring up weak areas of material (such as in front of and behind sink or cooktop cut-outs or even fissure veins) but is NEVER an acceptable method of supporting cantilever overhang (I know this is going to ruffle feathers of some fabricators) but let me repeat "NEVER". The fact is that, as a method of overhang support, it actually weakens overhanging material. You will not find this recommended by the MIA as an acceptable overhang support method.

Here is a link that might be useful: The Amastin Company- Concealed Overhang Support


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clipped on: 11.07.2011 at 11:24 pm    last updated on: 11.07.2011 at 11:25 pm