We understand/have learned the standard overhang off an island as 12″. But we need a longer/deeper one (18″ or more), because I am the shortest family member at 5’10” and we all need the room for our legs. However, our island is finished on all 4 sides with drawers and shelves, so there is no room for corbels or brackets.
We’re down to 3 fabricators who have the Uba Tuba granite slabs we like. They’re differing in price, of course (from $9,000 to $12,000 – we have a large kitchen and a big island).
But where they’re really differing is in their methods, and thus this is where I need your help in sifting through what they’re telling us, about our island and about their templating and installation/fabrication methods, in general. PLEASE HELP US UNDERSTAND AND DISCERN LIES FROM TRUTH!!!
1.a. Will steel rods or plates embedded into the underside of the granite weaken or strengthen the slab at those areas? (the granite is cut out so the steel is flush with the underside of the stone and then the steel is epoxied in).
1.b. One fabricator showed us a steel plate that is about 1/2″ wide and about 1/4″ thick (my best estimate without a tape measure). Is that good?
1.c. Are steel rods (round) or steel plates actually used? Which is stronger?
2. Are these rods/plates installed to support the granite during transportation or do they help support the granite after installation, as in using them to support an island overhang/bumpout like ours?
3. Some always install these rods/plates in the narrow areas in front of and behind the sink. Again, is this support mainly to prevent the granite from cracking during transporation?
4. On our island, if we can get a curved overhang/bump out of 18″ or more at the center, and as I said we can’t use brackets or corbels attached to the island, will installing steel rods/plates on the underside of the granite in the direction of overhang help support the overhang, or are we being sold the idea that it will help, just so they get our business? (the steel would be installed perpendicular to the edge of the island cabinet, starting somewhere over the island cabinet itself – like a beam extending from inside your house, to outside your house to create an overhang or an eave)
5. Has anyone heard that the epoxy used to “glue” in the rods/plates as only being warrented or lasting for 2 years?
6.a. Do clips screwed and epoxied into the granite really hold a vary large, double bowl stainless steel undermount sink strongly enough when the sink is filled with water and pots and pans and dishes and things?
6.b. Has anyone ever installed the undermount ss sink by sandwiching it between the plywood dust cover (with the edge of the dust cover routed out just deep enough to allow the lip of the sink to be level with the dust cover) and the granite slab, without clips but instead with epoxy on the bottom and top sides of the sink’s lip? (this is what our carpenter did in his house….who’s job used to be to install high end kitchens. He swears this is the better way and is only trying to get us to do in our house what he would do in his own house. He thinks the clips are used by everyone just because for the fabricators, it’s the standard thing to do and it’s so easy to do).
7.. Two fabricators always scribe the stone to the wall and any cabinets on the side. The third one charges extra (for our job, $300-$400 more) to scribe, because they usually count on customers having 4″ backsplashes to cover the gaps. Is it standard in the industry to include scribing in the template process?
8. The same fabricator that charges extra for scribing also doesn’t install steel rods/plates at all, but will if we ask him to. But we need to know if the rods/plates are helpful or not in our island overhang situation…..we don’t KNOW if we should ask for them or not!!! (that’s why I’m writing you here in the forum!!)
9. The fabricator in #9 also uses cardboard to template (at least that what I saw in the shop) whereas the other 2 that scribe use lengths of what looks like 1/4″ luanne plywood. Any pros or cons to either templating method?
10. Anything else we should be asking or be on the lookout for?????
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Replies
do use all those exclamation marks and caps when you ask those installers? And to trap the sink between plywood and granite would make change later of the sink a little difficult, no? Here's a recent discussion. Might try a search for granite countertop from more than a month ago.
Hi,
We'll be installing an 8' stretch of 35"-wide granite countertop in our new kitchen, with ten inches extending over the edge to make a bar/seating area. I'm shooting for a streamlined look, and want to avoid corbels or any other kind of visible support. The granite is 3/4" thick, with a 1.5" flat polish edge. There's no danger of kids bouncing on the counter, but I want it to be secure and in no danger of cracking, of course.
The cabinet and countertop guys haven't done this before. The best idea yet is a 1/2" thick steel plate, instead of plywood, under the entire 8" x 35" section. We have no idea how heavy it would be (or how much it would cost).
Ideas? I don't know if this is actually an unusual request, or if it's just a case of Oregon being a little bit behind the times. =)
Thanks!
/jen
It seems to me that some large (8") amgle braces would suffice for you and they could be hidden.
bobl Volo Non Voleo Joe's cheat sheet
Thanks! Perfect. Sorry, I usually search the archives before asking my rare questions, but didn't this time...busted!
/jen
A steel plate, 8'x35"x.5", will weigh about 475 lbs.
That plate alone attached to the top of your base cabinet, with no granite slab, and a 200-lb person sitting on the very edge of the overhang, would deflect .04".
If you went with a 3/8" plate, it would weigh about 350 lbs and deflect .09"
A 1/4" plate would weigh 240 lbs, but would deflect .30"
For each case, I assumed you attached the plate at the front and back edges of the cabinet. If you added a third attachement along the middle of the cabinet, you'd cut those deflections by more than half.
I don't have any material properties for granite, so I can't give you any deflection estimates for it. From what others have said here, granite varies quite a bit anyway.
I think I'd feel pretty good with 3/8" plate. With a little extra care in installation, 1/4" would probably do.
I found some numbers, but I don't have the equations. :)
The numbers I found for modulus of elasticity of granite range from 20 to 100 GPa, plus 1 at 7.3e6 psi. The 70 and 100 GPa numbers were from makers of granite surface plates.
My recollection from previous reading is that granite counter tops break before they show any appreciable deflection.
Hey Uncle Dunc,
Sorry I took a while to get back to you. I went home (Indiana) for a long weekend.
The equations I used were of the "back of the envelope" variety. I assumed the countertop was a wide, thin beam. (I later reconsidered that assumption, but I'll get to that in a minute.) Assuming beam theory, I split the solution into two parts - 1) the bending of the cantilevered part of the "beam" 2) the moment induced in the countertop where it joins the cabinet. The total tip deflection is then the bending deflection plus the moment times the overhang distance. (Does that make any sense? I didn't explain that very well.)
The tip deflection of a cantilever beam is P(L**3)/3EI, where P is the applied load (200 lbs), L is the length of the beam (10"), E is Young's modulus (28E6 for steel) and I is the moment of inertia ((1/12)bh**3. I equals 1.0 for a plate .5" thick and 8' wide, .125 for a 1/4" plate, .422 for a 3/8" plate.
For the .5" plate, the tip deflection turns out to be .0024"
The rotation due to the moment induced at the cabinet is M(L**2)/2EI. For the .5" plate, the rotation equals .0036 radians. Multiply that by 10" and you get .036" of tip deflection due to the moment.
Total deflection is then .0024" + .036" = .038" (I hope that's what I quoted in my first message:))
The evening after I posted those numbers, I began to question the validity of my assumptions. It clearly isn't a beam, especially since the load isn't distributed evenly along the edge. I came to work the next day and made a finite element model to get a more accurate solution. While I was at it, I studied the defelction due to 200lbs at a free corner, as well as 200lbs over a butt-width area in the middle of the edge.
To make a long story short (is it too late for that?), a .5" plate would deflect .05" if a 200lb person sat on the corner and .016" if they sat on the edge. For the 3/8" plate, the deflections were .11" and .038". Those numbers were close enough to my rough calculations that I didn't post the new ones.
I also run some numbers with a granite slab on top of the steel plate. However, I wasn't sure what to do with the numbers once I got them. Not only is granite quite brittle, it is also not homogeneous - there are veins and such in the material that will crack very easily.
After considering this over the weekend, I've come up with two conclusions.
1) You shouldn't count on the granite for ANY strength. Size the steel plate to take all the load. Any contribution from the granite is a bonus.
2) Even if deflections are large enough to crack the granite, I'm not sure that's such a big deal. First, a 200lb person sitting on the counter is pretty extreme. Second, the crack would likely be a very clean break and might not even be noticable once the person moved and the crack closed.
My recommendations are still that 3/8" plate would be fine, .5" plate is overkill to some degree, 1/4" plate could work but would not support anyone who sat on the corner.
__________________________________________
Remodeling Contractor just outside the Glass City.
http://www.quittintime.com/
I'm not a granite installer, but have done lots of kitchens that were done w/ granite. Any steel imbedded in the granite will help strengthen the counter - I have seen stainless dowels used, but not plate stock.(Which isn't to say that would be bad-I think it may be stronger.) 18" is a huge overhang-can you use a thicker roughtop? Maybe reinforce the roughtop as well? I've not heard about the epoxy only being good for 2 yrs- but again, that isn't my job. I've also not heard of reinforcing the slabs for transport.
As for the undermount sink - I do what your carpenter did for stainless sinks.
seems like scribing would be included in the bid- but most counters will have something used as a splash that would make scribing not necessary.
Almost all of the jobs I've done had no steel in the slabs. Again, 18" is a huge overhang. Something will need to be used support that stone.
As for the template material- 6 of one, 1/2 dozen of the other-
are your cabinets frameless or do they have face frames? Here is how I am doing my corbels- see attched- they are cantilievered(sp) out of the cab by attaching to an interior divider or something and saddled in a routed notch in the face frame.
Hope I was of some help...
I am answering your questions somewhat randomly here.
I never install sinks without rods. They definitely provide insurance during transport but they also help out if your house settles over time. They act like rebar in concrete ie it wont prevent cracking but it helps keep the crack from seperating.
I use round stainless rod. I would prefer rectangular stock but it is not as readily availible. I use a true two part epoxy. I have had questionable luck with polyester resins ie Akemi and suspect this type of adhesive may be the one with a two year warranty. Most of the reputable fabricators I know use Touchstone two part epoxy for rodding stone. Many people call polyester resin "epoxy". Polyester resin uses 3 to 5 % ?hydrogen peroxide? catalyst to cure the resin. Epoxy is usually mixed in a 1 to 1 or 2 to 1 ratio of resin to catalyst.
I much prefer hanging the stainless sink in a plywood cutout. Usually if it is routed out the sink doesnt seal tight enough against the granite for my liking. The adhesive between the slab and the stone usually raises the slab enough to accomodate the thickness of a stainless sink.
If the shop doesn't scribe as an included feature I would question their ability to template accurately.
For templating I can't imagine anyone using cardboard. The shop that uses the plywood strips is using what appears to be the industry standard and I am totally convinced it is the most accurate method to transfer cabinet layout to the slab.
On the overhang don't expect anyone to give you a guarantee. If someone wants to break off or crack an extensive overhang nothing willl stop them. If it is in a retired couples house it will probably last forever, if it was in my parents house in my high school years it would have cracked in the first year. Ubatuba is a good stone but the last slabs I picked up had a few cracks in the slab to start out. I cut around them but I find this material may be slightly more prone to cracking than others. If you look at it up close you will see it has microscopic fissures all through it.
Ubatuba is tough to polish well. It has a depth or clarity like a piece of glass that will be cloudy if not polished sufficiently. My credit union has ubatuba counters and the polished edges have all dulled as I suspect the fabricator used wax to bring out a shine. Some disreputable shops will even spray some varathane on a poorly polished edge to bring out a shine. Wet diamond polishing pads from 500 grit up to 3000 grit and finishing with a buff pad or polishing powder is the only way to do it right.
Keep researching your fabricators. Ask for the name and number of the last client they did ubatuba countertops for and see if you can look over the job or at least ask if they are 100 percent satisfied. Also ask for the contact info on their three most recent jobs and interview those references. There are so many questionably qualified fabricators out there that you can easily end up with a very disappointing end product.
I see alot of terrible granite installations and it is difficult to remedy a bad install once it has gone in. Fabricators who do shoddy work will try to convince you their level f of quality is normal or acceptable and are usually more interested in getting paid than giving you complete satisfaction. I only say this to emphasize that you have to be totally confident in your fabricator before he starts because once the granite has been installed there is not much you can do.
Ubatuba is a good choice of stone. It is so dense you won't have any problems with it absorbing stains. In fact my experience and what others tell me indicate it is totally unnecessary to seal ubatuba and the some sealers may actually cause more problems than they prevent. ie water spotting and cleaning problems.
Karl
One thing to add about the steel reinforcing. While it may not stop 100% of cracks on this large overhang, it makes it considerably more safe to be around, should a crack occur as compared to letting the slab eddge fall off onto your toes. With steel, even if the piece cracks apart, it will be suspended. And the steel makes it less likely to crack in the first place.
I know some retired people who could give the teenagers a run for their money....
Excellence is its own reward!
We did a kitchen in January, and the customer insisted on ubatuba. I bid corian, she wanted stone. She ended up at Home Depot, and got it for $56.00/sq/ft installed....about half the cost of the corian. I must admit, they did an exellent job, it looked great, fit perfectly.
They rodded the sink cut-outs, and the breakfast bar was only a 12" overhang and was rodded also.
I think ubatuba is the cheapest stone out there at the moment.
Right.
Last three comparrissons I did, the granite was less expensive than the corian..
Excellence is its own reward!
Home Depot?!?!?!??! Good price, too! Never would have thought of them for the granite, although I see it in the their kitchen displays. Hmmm. I usually don't think of using them for stuff requiring precision (no offense to anyone....). I will go there today.... and check them out.
I sure do appreciate everyone's feedback here on all my concerns and questions. This is the best forum I found.
I have concluded I will try to get by with a less-deep curved overhang, but I'm still going for the max that I can because we tall people need it. I sat at a display with a 12" straight overhang and my knees were right on the cabinets and because of that I was too far away from the counter to be comfortable eating there. The same place had another counter top/display set up with an 18" curved over hang and it was better.
I'm a professional builder, and my reply to this post went against every fiber of my being.
This particular kitchen was for a customer, whom we had added onto their house 3 times in 3 years, tripling the size in the process. I agreed to do a kitchen at cost if she came thru and got me 3 more jobs from friends or family that were at or above what we had done to her house. SHE DID IT. My word is golden.
I got her prices for granite, marble and corian. She choked(and so did I). She settled on the ubatuba, and went to the stone yard to pick out her pieces. The next day, HD advertised the ubatuba at $56.00 sq/ft. So she went in , took the plan and they quoted 1/2 price of my ubatuba price. Mine was my bone cost from the fabricator. I tried to talk her out of it, the whole Home Cheapo thing, how I could not guarantee, blah, blah, blah. She wanted to risk it....good for her. She pre paid, and they said they would send out the template guys in 2 days. Guess who showed up to template..........my fabricator. Guess which stone slabs she picked out....same she picked out 4 days earlier.
Yeah..I demanded answers.......fabricator said HD just gave them a contract for at least 180 jobs in the next 8 months, for this price. But they had to honor the sq/ft price, warrant the jobs, and do all the callbacks.....he jumped on it.
I had some explaining to do to her about the price disparity(was I really giving her bare bones cost or jacking her)....so I just produced the quotes, and explained what the fabricator had told me.
Her Kitchen came out perfect....she had less than $30K in it. Was she happy? Well, yesterday we dug the foundation for a 120K addition on her best friends house. I'm thinking about putting her on the payroll in sales.
Keith, I am curious how Home Depot applies their $56/sq ft price. I assume that is for a typical 1 1/2" bullnose with a 4" backsplash? Does that price automatically include a polished bowl hole for an undermount sink, cutouts for any electrical outlets, polished returns, drop in stove tops,etc or do they have standardized charges for additional work. If you recall any of their additional charges I would love to know. If not I could just go in posing as a customer and get it straight from them.
As much as I avoid Home Depot I would send someone their as well if they are guaranteeing satisfaction on the installs. So many shoddy fabricators are springing up that it is tough to refer business with confidence. The one HD install I heard of locally was not to the customers satisfaction so they tore it out and did it over againg at no charge.
Thanks, Karl
The National Kitchen/Bath Association recommends the following for counter overhangs:
Barstool height: 12"
Counter height: 15"
Table height: (regular chair) 18"
The reasoning is that the lower the chair you're sitting on, the deeper yous lap becomes. YMMV
"A completed home is a listed home."
Yo Lisa, am I confused or did you mean depth instead of height? My knees won't fit under an 18" table unless I'm sittin on cushions on the floor.
{:<).
Excellence is its own reward!
LOL! OK, let me see if I can be more clear. What they mean is that a overhang on a bar-height counter (42" high, I think) should be 12" deep; the overhang on a counter-height counter (36") should be 15", and a table-height overhang (29" high) should be 18" deep. I guess it goes to follow that if, indeed, the counter is only 18" high, the overhang should be deep enough to straighten out your legs while you sit on that cushion. That would work for one of those dinners with a belly dancer, eh?
"A completed home is a listed home."
I don't know? Will you be doing a belly dance when I come over for that steak dinner? after removing tiles, I'll be down on the floor already!
LOL!.
Excellence is its own reward!
To Karl and Keith: That is some story about your client and HD. I did check them out last week, and their current pricing for Uba Tuba in my area is $72 / sq foot, which is about $10- $15 lower than quotes I've gotten from stone fabricators. I may pay for HD to come and measure though and see what they come up with for footage and for total price. That $30 is refundable but is applied to the total cost should I go with them for the job. I'm going to go the supplier they use on my own and see what they have for slabs. Maybe it will be the best we've seen and HD will get the job!
To Lisa: The fact that overhangs can be between 12" and 18" makes me feel quite confident that I can safely get the 18" overhang we need at counter-top height (even though your response said 18" at table height). Spouse and I did some tests this week, overhanging plywood from our island and sitting there with stools, and we need at least the 18" at counter top height to handle our very long legs (I still prefer 20" cause my legs are longer). We also need the distance to keep our toes/shoes from hitting/marring/denting our island cabinet.
I've made countless spec'ed corbel/brackets for granite bar height tops. They all seemed awkward and knee knocking. And curved counters got pretty pricy. We're going to use 3/8" steel plates under the next job...I'll get all the specs and post them next week...I think it could handle any hormone infested teenagers or likewise afflicted retirees....
Always trying to get over the humps, bb It's okay, I can fix it!
Please forgive if I have missed something, which happens regularly for me, but would it work to put some nice legs on each end, with some sort of bracing between them? I'm not aware of all the details, but have seen pictures of nice Island/bars with what appears to be Large table legs supporting portions of the overhang. Just a thought, take it for what it is worth, or what you paid, which ever is larger.
Dan
We think alike!! Yes, our plan the entire time has been to anchor posts into the floor over the floor joists at each end of the island's granite bump-out and then have our kitchen cabinet maker build us pillars (either round or square) whose halves will fit and be secured around those internal support posts. These pillars will be somewhere between 6" to 9" out from the corners of the bump-out side of the island cabinet. The pillars will match our cabinets in wood and stain and the flutes will match the decorative pilasters he's installed at the corners of our island and elsewhere around certain cabinets.
We just don't want one of these decorative posts/pillars smack in the middle of the bump out....it will be ugly and get in the way of seating. That's why we are concerned about how far out the bump-out can go, spanning these two posts/pillars that will be 5 feet apart, without using a post in the front middle and without using brackets underneath.
Attached is my best attempt at drawing with a computer (I prefer drafting on paper) Island cabinet is 4' by 7'. Granite will bump out 18" at the deepest point in the middle, supported on each end with posts. Top view shows posts under the ends and dotted line shows edge of cabinet. Side view shows posts separate from and in front of cabinet, with granite on top of island and posts.
If you're planning on legs...why can't tabletop-like supports be designed....pretty much hidden.....and tied in the legs?
I'm thinking wood...like a regular table......or welded up metal.....of more support is needed. Something could run on the flat.....from outside edge....and attach to the island cab's....to support the middle of the slab.
Jeff.......Sometimes on the toll road of life.....a handful of change is good.......
The HD price was a sale, that they seem to have every year around Feb. to kind of spur sales along in the dulldrums of winter. Still ,the everyday price is a deal compared to retail at a kitchen shop or stone fabricator.