SFA

On a 24 inch wide cabinet what would your max overhang be for a seating area? 16 18 or 20 inch?

12"

9" and no more than 12". I get nervous about tipping not breaking.

Are you talking overhang on 1 side or both sides?

Any overhang over 10" get support brackets of some kind

Ken is correct, pertaining to 3cm:
From MIA Stone Design Manuel V8

O, by the way, Version 8 of the Stone Design Manuel is FREE!
Download it and read, great CYA!
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Solid Rock Oregon wrote: ↑

Fri Mar 24, 2017 5:00 pm

On a 24 inch wide cabinet what would your max overhang be for a seating area? 16 18 or 20 inch?

Thickness?
Material?
Are you asking unsupported overhang?

I had a 2cm Caesarstone Champagne Limestone island that was about 8' long and had a cantilevered overhang of 12" off the back of the island for seating. It did have a 3/4" plywood sub top to help support it a little. I felt that was the max I could get away with and not use corbels. It is pretty strong material, but, that was a gamble. My kids hung off it like it was a playground... ONCE. It held fine but they knew not to do it again.
Looking back, I should have put steel supports in the plywood to be safe. I sold the house and the new people tore it out anyway, so no worries.

Ken Lago wrote: ↑

Fri Mar 24, 2017 5:38 pm

9" and no more than 12". I get nervous about tipping not breaking.

Ken brings up a good point about tipping. Once you start going out past 12", even with supports, you need to be sure the opposite side of the cabinets are secured well to the floor.

Solid Rock Oregon wrote: ↑

Fri Mar 24, 2017 5:00 pm

On a 24 inch wide cabinet what would your max overhang be for a seating area? 16 18 or 20 inch?
[

Let me clarify. there is steel supports from the granite bracket company that will be in place.

Not exactly a clarification but we already given all the information you could possibly need.

For what it is woth I have a 24" wide island in my kitchen with a 12" overhang all around, no supports, Ubatuba. I also have a isnd in my kitchen same size same over hang in Bourduex.

Quartzite bob wrote: ↑

Mon Mar 27, 2017 2:20 pm

For what it is woth I have a 24" wide island in my kitchen with a 12" overhang all around, no supports, Ubatuba. I also have a isnd in my kitchen same size same over hang in Bourduex.
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That is far beyond any spec. They may not fail, ever. BUT, if they do, your insurance company will look to pin the liability on you (& rightfully so). I hope no one gets injured.


IMO, poor advice is not worth anything to the well informed.

Dan R. wrote: ↑

Mon Mar 27, 2017 7:00 pm

IMO, poor advice is not worth anything to the well informed.
[

It probably worth what it cost

Ken Lago wrote: ↑

Mon Mar 27, 2017 12:53 pm

Not exactly a clarification but we already given all the information you could possibly need.
[

Ken
I thought it needed clarification that there would be steel supports since the bulk of the replies where about overhang past the cabinet only.

Is tipping going to be an issue?, what type of steel supports? what type of stone? is it an island or up against a wall?

Solid Rock Oregon wrote: ↑

Mon Mar 27, 2017 12:07 pm

.......
Let me clarify. there is steel supports from the granite bracket company that will be in place.

Ask them.

Those brackets will certainly prevent the granite from falling on someone's foot if it cracks. More importantly, how will you prevent the cabinet from tipping over when a big guy decides to sit on it?

So wait... whats the rule of over hangs all around an island? If you are saying max 6", can you do 6" on both sides of the cabinet. I dont understand how it says 6" yet ot also says no more than 1/3 of the countertop which is 12" per 24" cabinet

Amroczka wrote: ↑

Fri Mar 31, 2017 12:39 am

I dont understand how it says 6" yet it also says no more than 1/3 of the countertop which is 12" per 24" cabinet

The 2/3:1/3 is a secondary qualifier that could LIMIT the overhang to less than 6" (2cm).
This rule is to avoid the top from "tipping" in the event additional weight is applied to the cantilever.

Examples:
24" top - (2/3) 16" supported can have (1/3) 8" unsupported in 3cm, but limited to 6" unsupported in 2cm
18" top - (2/3) 12" supported can have (1/3) 6" unsupported cantilever in (2cm or 3cm)
12" top - (2/3) 8" supported can have (1/3) 4" unsupported cantilever (2cm or 3cm)
Typical 24" cabinets would default to the 6" unsupported for 2cm and 10" unsupported for 3cm.
Key word above is UNSUPPORTED.

DSDM v8.0 wrote:Cantilevered countertops exceeding these dimensions will require corbelled supports beneath the stone.

Hardly anyone believes me when I tell them anything over 10" needs support. One of the most misstold truths in the industry is "my cabinet people and builder says it's 12" "

Mark Meriaux wrote: ↑

Fri Mar 31, 2017 8:46 am

Amroczka wrote: ↑

Fri Mar 31, 2017 12:39 am

I dont understand how it says 6" yet it also says no more than 1/3 of the countertop which is 12" per 24" cabinet

The 2/3:1/3 is a secondary qualifier that could LIMIT the overhang to less than 6" (2cm).
This rule is to avoid the top from "tipping" in the event additional weight is applied to the cantilever.

Examples:
24" top - (2/3) 16" supported can have (1/3) 8" unsupported in 3cm, but limited to 6" unsupported in 2cm
18" top - (2/3) 12" supported can have (1/3) 6" unsupported cantilever in (2cm or 3cm)
12" top - (2/3) 8" supported can have (1/3) 4" unsupported cantilever (2cm or 3cm)
Typical 24" cabinets would default to the 6" unsupported for 2cm and 10" unsupported for 3cm.
Key word above is UNSUPPORTED.

DSDM v8.0 wrote:Cantilevered countertops exceeding these dimensions will require corbelled supports beneath the stone.

[

Ok thanks for clearing that up. In your examples you say "24 top", is that the top or the cabinet?

So if I wanted a 36" top on a 24" cabinet that leaves a 12" overhang on 3 cm or 34" top with 10" overhang on 2cm... (2/3) 24" supported can have (1/3) 12" unsupported in 3cm or 10" 2cm


Correct? Or am not understanding still?


I guess im just stuck on the whole... typical 24" cabinet can only have a 6" overhang in 2cm when it also says the same 6" limit for a 16in cabinet.. not that i ever put any overhang with 2cm without a plywood substrate under it also but still. I just want to know whats correct

Solid Rock Oregon wrote: ↑

Fri Mar 24, 2017 5:00 pm

On a 24 inch wide cabinet what would your max overhang be for a seating area? 16 18 or 20 inch?
[

You don't say what material. On engineered stone, most manufacturers allow up to 14" of unsupported cantilever, some 15".

Amroczka wrote: ↑

Fri Mar 31, 2017 11:38 pm

Ok thanks for clearing that up. In your examples you say "24 top", is that the top or the cabinet?

So if I wanted a 36" top on a 24" cabinet that leaves a 12" overhang on 3 cm or 34" top with 10" overhang on 2cm... (2/3) 24" supported can have (1/3) 12" unsupported in 3cm or 10" 2cm

Correct? Or am not understanding still?

I guess im just stuck on the whole... typical 24" cabinet can only have a 6" overhang in 2cm when it also says the same 6" limit for a 16in cabinet.. not that i ever put any overhang with 2cm without a plywood substrate under it also but still. I just want to know whats correct

top=countertop

I think you've almost got it. The 2/3:1/3 rule is to account for "tipping", not the failure of the stone itself.
The 6" (2cm) and 10" (3cm) are to account for physical limitations of the stone.
Any stone (no matter base dimension) beyond 6" in 2cm and 10" in 3cm is recommended to have additional support.

FWIW, MIA+BSI does not govern ANY manufactured products. They each produce their own technical information and warranties. Some choose to adopt MIA+BSI standards as a recommendation.

Mike:

There are lots of sound ways to support stone and estone, however, you cannot support a 20" 3cm cantilever with a couple of 1/4" aluminum pieces on the flat screwed to the top plate of the wall:
Well, you can, but you'll tear the stone without even breaking the seam:
The most cost effective repair is ugly, but does not budge when the triangulated supports are mounted over the wall studs:
More here: http://www.countertopiq.com/2017/03/31/ ... -failures/