Our granite was installed without supports for overhang

jules1906

15 years ago

It just occurred to me today (thanks to someone on here asking me) that our granite (installed on Fri.) does not have anything supporting the 11 1/2-inch overhang! Can someone please tell me the standard length for which you need supports? I thought it was around 8 inches. We have decorative cabinets all around, so we can't hang L brackets up (not that I would want to do that anyway). Any advice on how we can get this rectified? Should we make the granite installers redo the whole thing? My husband is happy with them just cutting the granite and getting rid of the overhang, but I am not happy with that idea! I feel like they should fix it if necessary. Do we definitely need a support?

Also, my husband noticed that when he opened up the drawer on the island he could see daylight peeking through underneath the granite. Can that be fixed?

Any advice you may havae would really be appreciated. Thanks!

I'm sorry, this isn't the best photo:

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Comments (11)

ccoombs1
15 years ago
Here's a great thread for you. According to the thread's author, 10" is the max unsupported overhang you can have with granite. I'd make the fabricator come back and do it right!

Here is a link that might be useful: Stone checklist
User
15 years ago
The biggest problem that I forsee with throwing it on to the shoulders of the stone fabricator is that the cabinets themselves have to be designed from day one to have the internal support to be able to support the granite. You have to have some sturdy attachment support for the corbels or brackets. Or, your GC or granite fabricator has to be one that offers steel support bars under the granite. This has be be at the door of the GC to solve, as it's a multi trades task.
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We have a 60" long x 18" wide overhang with our island. Our granite guy said we didn't need to support it, but I beg to differ and supported it just in case. We drilled a 3/4" plywood sheet (just smaller than the entire island)into the top of the cabinets and then routed in 1/2" steel bars (these were also just smaller than the island) and drilled these into the plywood. The granite was laid on top (and glued/epoxied). Although you can't see the plywood unlesss you bend over or are sitting under the overhang, we chose to cover the edges of the plywood with thin strips of wood that matches our cabinets, so it looks like the support extends as part of the cabinets. We did all this because we wanted a clean look with no corbels, etc. It is great (I had to stand on the island to change a light bulb) and I am very happy that I chose to support it...now I don't have to worry!
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Folks- Let me just point out that the stone (3CM most likely in this application) will need to be adhered to the pony wall and the cabinet assembly with an adhesive of some sort - latex caulk, silicone, polyester or epoxy (I use latex caulk and sometimes silicone) to "freeze" the stone assembly to the substrate. The stone (IMHO) should never be just "set dry" on any substrate. The overhang intel from MIA is indeed designed to deal with the fulcrum effect that a piece of stone will develope - when more of it's mass is not supported by a substructure - ie: pony wall or cabinet assembly.... I am NOT an Engineer.. (I should have been cuz I love the structural stuf and all) but alas - I am just a Fab-Ri-Mi-Cator that's been doing this Natural Stone gig for 24 1/2 years now. and I have seen, done & learned a lot over the years. We are ALL in the learning curve at all times - it is just that some of us have been in the curve longer than others..... Thanks for all of your kind words - I hope that you'll benefit from my ramblings. You can also check out my consumer education website at natural stone 101.com. I will be posting pod-casts on various topics on Natural Stone that are brought up by consumers. kevin
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You'll need new skins, wider than 48''. Detach the full height cabinets under the proposed overhang. Attach 2 2x4 pressure treated pieces of lumber to the slab with a Hilti or ramset where I show the RED lines. Also use some construction adhesive. Yes, I like belts and suspenders. :) Build a 34.5''H pony walls with conventional framing techniques, taking the wall to the end of the cabinets. Attach the existing cabinets to the pony wall. Reattach the full height cabinets to the pony wall studs. Here is where you will need the custom steel for the 33'' long steel pieces (BLUE) needed to support the overhang. You will also need 12'' ones for the side overhang. They cannot be flat steel, as that is too flexible. 1'' tubing is too thick for your full overlay cabinets, even with the doors adjusted as far down as they will go. You could use 2''W flat 1/4" steel with a 3/8'' ridge welded to it to create rigidity, in a T shape, flat side up. Holes would need to be drilled into it to attach to the pony wall. Once the steel is sourced and created, you can rout out the pony wall (2 step process, once for the ridge, once for the flat stock) and top of the face frame to accept it. Once the steel is attached, then the skins (GREEN) can be applied to the sides and ends to cover the pony wall. You may want some Outside Corner molding and Batten molding as well to hide the seams. This is a serious design deficiency on your KD's part. He should arrange for the cabinetry materials gratis, and also pay something toward the steel. Labor for this will need to have good experience dealing with finished cabinets and routing, so let the KD pay something towrds that as well.
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I review the plans of everyone working on my house. [...] My general contractor and the granite fabricator/installer will warrant their work, and like everything else going into my house, I want to double check, and I want them to justify their plans if they differ from what I have learned from Professor Google. We don't have their plans though, if that sketch was given to you as their plan for support, then you are in trouble and need to hire another professional. To evaluate their plan we need to know what system they plan to use to limit flex. Make a wall beyond the cabinets, or close in the ends. for additional support. I am not a huge fan of walls that dissect long pieces of granite unless the people building the walls really understand what they are doing. I think the post is a much better idea that accomplishes substantially the same thing as a wall. ----------------------------------- When we talk about supporting granite we are talking about one thing. Limiting the tensile pressures. Granite, just like concrete, has great compressive strength and rotten tensile strength, when granite flexes you get compressive force on the concave side and tensile force on the convex side. Moving from theory to reality in granite we really have to do three things, (1) limit flex, (2) limit movement and (3) avoid isolation. Many inexperienced people will address movement and flex while ignoring isolation and when that happens you get the result that Joseph posted above. If we look at the brackets that are often used for granite islands we can see that their real purpose isn't to stop movement but to avoid creating a fulcrum so that the entire sheet of granite moves together. http://www.countertopbracket.com/countertop-island-support-brackets-hidden-p/ib.htm I guarantee you that something heavy placed on that overhang will cause the countertop to tip slightly in that direction, but the brackets ensure that the movement is carried past the edge of the cabinets so that the entire piece moves rather than creating a fulcrum at the back of the cabinets that isolates the overhang from the cabinets. Too much movement must be avoided because then you get the shock of the cabinets moving which can be bad so walls in long islands may be necessary but when they are you must avoid isolating them. In other words, in Joseph's example above had the brackets been extended and tied into the cabinets in such a way that the entire piece was tied together or tied to the cabinets sufficiently that everything moved together, the break is unlikely to have occurred. Technically the brackets in Joseph's post above did exactly what they were designed to do. They eliminated breakage at the fulcrum...They just created a new fulcrum because their designer didn't understand the problem. From a physics stand point, a post is nothing but a very short wall. You can get substantially the same results from a post that you can from a wall, by adding cost. Essentially the white arrows would be a wall while the red arrows will be a post. So long as the post doesn't flex more than a wall (which it will compress less than a wall), mechanically you can achieve the same thing. However, you create more isolation points, all of the red arrows need to either have very little movement at all, or be tied together in such a way that they move together (note the arrows actually form a circle). Achieving no movement is much harder than tying them together in such a way that the limited movement extends through the area. A 2" tubular frame under the entire granite surface would absolutely be preferred, as that is the best way to carry movement to the entire counter. My original advocacy for plate was in opposition of L brackets rather than a tubular frame, to avoid isolation. I think you can achieve much the same result with a steel plate (a 36" steel plate is roughly equivalent to about 20 brackets) but I am not opposed to a tubular frame, especially if you are going as deep as 2". Anyway, this is just my 2 cents. In the end, to evaluate the solution that your contractor is using we need to know that.
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davidro1
15 years ago
I guess the installer stretched the limits. Happens all the time. I have seen bigger unsupported. The homeowner loved it, "Nobody is going to sit or stand on the counter" is how she justified having it like that.

Talk to the guy. The visible gaps concern me more.

David
ccoombs1
15 years ago
You could install some corbels under it to support it. I would not leave it unsupported. I have grandkids and you know how they can be! I can just picture a kid climbing up there for something and the granite snapping off.
Buehl
15 years ago
Corbels will only work if the island back is more than just cabinets w/decorative doors....I seem to recall you also need a 3/4" wood panel for support...I know something like that was done to the back of my peninsula to support the corbels.... We have a 15" overhang.

Perhaps Kevin, Joshua, Mimi, Paulines, or other stone guru will chime in. I think Live_Wire_Oak mentioned this on a different thread a month or so ago.... (Hence her comment "...the cabinets themselves have to be designed from day one to have the internal support to be able to support the granite...")
gobruno
15 years ago
We don't have supports on our granite overhang and have never had a problem. 2 houses ago, we had a 12 inch overhang that was about 8 feet long. This house and the last house had an arched overhang that was 10 inches on both ends and 15 inches in the middle. It was 8 feet long in the last house and about 6.5 feet in this house. Since the granite is 1.25 inch granite, all three times, we were told that a support wouldn't be necessary. Honestly, we've never had a problem, and our counters have taken a lot of abuse. Our kids like to stand and sit on the island, and It's not been a problem. I don't know, may be over time it will weaken, but so far so good.
slc2053
15 years ago
How wide (or deep) is your countertop in total? I'm being a bit extreme in my example but if you have a 2 foot wide counter and 11.5 inches of that was unsupported then you'd have the countertop tipping over very easily. However, if your coutertop is 4 feet wide (or deep) and 11.5 inches of that is unsupported then the weight of the supported side is more than adequate to keep that countertop from tipping towards the unsupported side. We have a 3 foot wide counter that is 6 feet long and 10.5 inches of that is unsupported and I can sit (105 lbs) on the unsupported side and it doesn't budge!

But, you also didn't indicate what your concern is...are you concerned with it tipping or with your cabinets not being able to handle the overall weight? I'm assuming the tipping issue, but didn't know.

Also, they should have put a bead of silicone or something to seal the coutnertop to the top of the cabinets.

HTH...
wa8b
15 years ago
Ordinarily, unless it were a part of the specification and agreed upon at the time the stone was ordered, it's not up to the stone fabricator to come up with supports for the slab. Any supports would be a part of the cabinetry. The stone fabricator simply provides the stone in the specified size, thickness, and finish.

If your stone fabricator didn't agree to supply a support system, I don't think you can go back to him at this point, unless you're willing to pay for any extra after-the-fact work.

That being said, if the fabricator thought there might be a problem with an unsupported overhang, it would have been nice of him or her to mention it at the time the stone was templated. It's entirely possible that in your fabricator's opinion, an 11-1/2" overhang is nothing to worry about.

Was a kitchen designer involved in your project? If so, that's the person to whom you should be talking.
jeanar
15 years ago
Another option, we have 4" square legs that go to the floor supporting our overhang.
jules1906
Original Author
15 years ago
Thanks for all the comments and advice. I'm just sitting here the last couple days not really knowing what to do. Our GC isn't worried about it. He has a friend who is a fabricator whom he called for advice and he wasn't worried about it. Our plumber also works for a granite company and said their guideline is 12" for adding supports to an overhang. Of course, I called the installer and they also said they use supports for 12" and over. All this makes me feel somewhat better, yet after reading other comments there is a part of me that can see myself constantly watching over the kids over the years as they go to lean on it when doing their homework, eating, or simply hanging out. Ugh! Thanks again for the feedback. We are not quite sure what to do, but are definitely sending the installer a letter.
sunnyd_2008
15 years ago
I agree that 12" is the max without support
If you really feel uncomfortable price supports with your cabinet company to match cabs. or maybe you could add matching legs
Sometimes the granite fabricator can put thin steel supports in under the top, but I don't think it's necessary
It's highly unlikely that it would ever tip over so don't worry about that....

Our granite was installed without supports for overhang

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Our granite was installed without supports for overhang

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