We’re having 3 cm (1.25″) granite slab countertops fabricated. I want to re-use my existing cast iron surface mount sinks. I’m getting conflicting info from the local experts. One said no — it won’t work. The guy who did the templating said the rim on these sinks is flat enough that he thinks they can do it.
This is a $1000 plus issue for me here. I appreciate any light you can shade on this.
“The road goes on forever, and the party never ends”
Robert Earl Keene
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Replies
just picked out 2 slabs todat so i feel the pain. watch ebay for a undermount cast sink. i did have one bookmarked if it's still there ,i'll check. i did buy a nice staimless for 215 the other day. also bought a AC stainless sink for a 100. didn't like it so had to buy the other one.win a few lose everything else!larry
When it does not work and you have an odd size hole in your not to cheap chunk of granite, think of the $ you saved...
Find a fabricator who is confident it will work or create and place the template for the fabricator within his template of the entire top.
Here's how it may typically be done. You need a sturdy base cabinet. Onto the sides of this cabinet, as well as perhaps the back and the front, you will need to attatch very strong support on which to rest the sink flange on in order to make the very top of the sink rim come flush with the BOTTOM of the stone countertop to which you will seal the sink to.
If your sink has holes for the faucet, you may not be able to pull this off.
Typically, the cutout in the top will be smaller in size as compared to the sink, thus you will have the effect of the top overhanging into the sink slightly.
Don't listen to the naysayers, and don't hire one to do the tops for you. I can't say for sure with out seeing your sink, but this type of install is common place today and any bona fide stone fabricatoe should be able to handle it well.
Good luck,
Eric
I Love A Hand That Meets My Own,
With A Hold That Causes Some Sensation.
I kinda agree with Firebird. The key here is to find a fabricator who is interested in making it work, not someone who just wants to do it like it's always been done.
Whenever you are asked if you can do a job, tell'em "Certainly, I can!" Then get busy and find out how to do it. T. Roosevelt
Do a search, I asked that question about 2 years ago.
Yes it is done all the times. First you reinforce the cabinet. I set mine on ledgers carriage bolted to all four sides in case I have to replace the sink later. Make sure the top of the rim is below the top of the cabinet, about 1/16" would be fine.
The cut-out can overhang the rim which is more forgiving or it can be right at the crest of the rim, then you'll see the caulk line.
Something else you have to watch out for is the faucet, make sure the one you have in mind can accommodate the extra thickness of the counter. Sometimes you may have to get extension bolts for the hold down.
You've already got some great info. but I'd like to add a technique I've used for a stainless sink. I had a client who wanted to do the same thing with a standard SS sink. We used a 3/4" plywood build-up on top of the cabinets to support the granite. In the build-up, we routed the depth of the sink ledge to bring the sink flush, then just dropped the granite on top. The lip of your cast sink will be thicker, but using 2 layers of ply [ 1 layer inset into the cabinet ] should do the trick.
There is no reason not to do this. If I were doing your kitchen I would be much more enthusiastic if you and taken a quarter sheet of 1/4" ply and cut out an exact template of the sink as you want the granite cut.
Someone said that holes in the sink deck for plumbing might cause a problem. I disagree unless the deck for the holes is recessed.
I use a product called a "sink setter" to support the sink and raise it up to the granite on screws that function like screw jacks.
http://www.vicintl.com/html/msc/go_to.htm#sink_set
This link is to a supplier that only sells by the case, but google it and you should find something.
Karl
Thanks for all of your replies. This forum is a fantastic resource (as is the magazine).
The issue doesn't seem to be how to support the sink. The fabricators haven't even mentioned that. (I have not talked to them directly. I have been going through the sales person for information. It may be time to talk directly to the fabricators.)
Their concern is hooking up faucets since we would be adding 1.25" to the thickness the faucet has to penetrate. The rim on my cast iron sink is about 1.00" thick already. My existing faucet, a four hole model (hot / spout / cold / spray) will definitely not work. The hot / spout / cold connect under the deck and there is not enough length on the "risers" to go through an additional thickness of granite.
The sink is white enamel on cast iron. My wife wants to keep white sinks. There don't seem to be a lot of choices in white undermount enamel on cast iron sinks. The ones I've seen are big bucks.
I looked for a manufacturer and model underneath it. I find metal tags with the following info:
"A.R." (probably the manufacturer, but who?)
"33 X 32" (obviously the dimensions)
"7 - 11 - 89 A" (I'm sure the date of manufacturer)
"No. 4" (???)
Is there a particular type of faucet that will solve this?
"The road goes on forever, and the party never ends"
Robert Earl Keene
I rarely work in 3cm stone (usually 2cm on west coast) and have only used it in bathrooms so I cant speak from experience on plumbing accomodating thick stone/sink combos.
I dislike stainless myself but that sounds like the common solution.
I recently installed a CECO cast iron sink that came without a deck or drillings to accomodate plumbing. You could buy one of these sinks for 400 dollars or so and drill wherever you want in the granite for faucets and not have any more than 3cm thickness to deal with.
I personally like wall mounted faucets. Have you considered this option?
Karl
Follow up to Can I Undermount Surface Mout Sinks
Just wrapped up my granite slab countertop project and I thought I’d share my experience. I encountered two issues with using a self-rimming surface mount sink as an undermount sink in a granite countertop:
1. The granite slab installer told me it was tougher for him to do his part because undermount sinks typically have about 3” diameter faucet holes. That’s an easy target to hit when you’re drilling a 1.25” hole from the top of the slab. My surface mount sinks have four 1.25” faucet holes, so the installer had to be very precise in his layout for the holes in the slab to match the holes in my sinks. There is, however, a little bit of leeway. As long as the faucet shafts fit through the hole in the slab and also the hole in the sink, you’re OK. Even though a couple of the holes were not dead on, I didn’t have any problems with this part of the installation.
2. The thickness of the slab (3 cm or 1.25 inches in my case) plus the thickness of the sink (0.25 inches for my cast iron sink) may prevent you from using certain faucets. I used Delta faucets and was challenged, but I managed to make it work. There was no issue with the main sink faucet because Delta offers a “thick deck mount kit” for about $10.
But they don’t offer the same kit for the bar / prep sink faucet. The Delta customer service rep told me he didn’t think it would work. But I studied the technical drawing for this faucet and determined the threaded shaft was just barely long enough for me to be able to attach the plastic nuts and the supply risers. So I bought it. Guess what? The Delta guy was right. I could get the finger tight plastic nuts on but then there was no room left to attach the supply risers (which require about .25” of threads).
So I headed to my favorite hardware store to improvise. I came home with a pair of .75” PVC female threaded couplings – the kind that are cylindrical on one end but hexagonal on the other. I chucked my random orbital sander in my vise and proceeded to sand down the hexagonal end of the couplings. I had a 12” piece of black iron pipe lying around so I temporarily screwed the couplings on the pipe to make it easy to hold them. I stopped when only about .125” of material was left. Then I hack sawed off the entire cylindrical portion, leaving me with .75” X .125” thick plastic hex nuts. That was just thin enough to enable me to screw them on tight and then have enough threads left over to attach the supply risers."The road goes on forever, and the party never ends"
Robert Earl Keen