I'm sure you would be fine just using a bead of silicon and the regular underside screw clamps. However, I, personally, would never do this. I want to be able to easily remove a sink if there are any future problems, or I wanted a different style in the future, or if I get any leaking around the edge that causes a problem with the integrity of the underlayment. I presume, though, that you have already thought of this and are fine with that potential downside. In any case, I wouldn't adhere the sink with epoxy.

Thanks for the input! We have thought about the disadvantages of sandwiching the sink in this way. It's a bit of a risk but the trade-off is what we think will be a pretty stunning built-in effect.

After talking with out tile guy today I think we're going to go with a basic construction adhesive followed by silicone sealer between the Rondec and trim.

It's a risk, but sometimes you've got to give it a shot... :)

This sounds like a lot of work and lot of tinkering to get it to be "just right". So the top edge of the sink will be flush with upper surface of the underlayment? If so, does that mean you intend it to butt up against the underside of the rondec? I suppose a ring of silicone will be used for that joint.

Please take pics along the way. Some of us would be interested to see how it works out. Good luck with it.

I just reread your post. If you are going to glue the sink to the underlayment, do you realize you will have an exposed edge of the underlayment to deal with? Personally, I don't think I'd epoxy a sink (that will get heavy from time to time) to underlayment. Doesn't sound solid enough. If you do go this route, use color-matched caulk for the grout edge of the rondec. Regular grout will probably crack with movement and vibration.

If the sink will be on top of the underlayment you will have to make sure there is never a failure of the seal from the tile to the sink.

Any failure here would allow water to get to the underlayment and damage it requiring extensive rework of the counter for repair.

The problem will be in even seeing if leakage is occurring until it has thoroughly saturated the underlayment and can be seen from below (if you remember to check).

Even with a membrane you can still have water issues if there is not a drainage path.

At the very least, exterior plywood with a painted on sealer on the edges and around the opening might help, but water can travel a long way in very small gaps through capillary action.

skibend-
One other point I'd like to make is that you don't typically see installs like this because of all the potential problems that have been pointed out above. I like to experiment, too, but not when it comes to possible water damage and major re-work. Sometimes the standard method is the standard method for a good reason.

Hi everyone,

Thanks for all of the advice and suggestions. We ended up going with a more traditional approach when dry fitting revealed that it was going to be impossible to get a good edge between the Rondec and the tile -- too many variables to feel like we'd have a positive outcome. So, the sink is in and we have a traditional tile wrap around it.

Thanks again for your help!

Thanks for the update. Sounds like a good decision from a rational approach, i.e. asking questions and testing it out. Applause for your effort.

Thanks...We're now looking at using the stainless steel Rondec we own :) as a trim for the range hood chimney. It doesn't quite meet the ceiling in all areas and I think the 3/8 Rondec could be just the right crown molding...