What’s best to stick granite backsplash to granite countertop

backsplashbathroomgranitevanity

Forgive my lack of knowledge here.

New bathroom vanity.
Black granite countertop and 3" tall backsplash.
Countertop, and will-be-visible faces of backsplash, are polished and factory sealed.

** Backsplash will be about 2" from wall **

What specific product is best to use to "glue" the backsplash to the countertop?
(googling seems to suggest some sort of epoxy, but wondering if that might be too brittle, or discolour…?)

Do I need to sand the polished & sealed countertop where the backsplash will sit?

Do I need to caulk when the "glue" is set, and with any specific caulk?

Here's the relevant bit of the "installation guide". There is no text…

excerpt from unhelpful installation manual

Thanks in advance…

**** EDIT ****
For clarification, the backsplash won't be against a wall but it will be near it. About 2 inches away. And we have little kids so I'd like to use the backsplash to stop stuff running down the back of the cabinet where it will be hard to clean.

Best Answer

Clear, slow (ie, not 5 minute set time) epoxy is what I'd use. Apply masking tape on the countertop exactly at the seam line. Same for the backsplash. Glue and set the backsplash (clamp gently in place), and wipe the joint clean of the excess. (Disposable gloves will be your friend, here, as epoxy is hard to clean.) Pull the tape and wipe the joint one more time. Have whatever recommended solvent on hand for cleanup in case you get any epoxy where it shouldn't be.

My gut feeling is that this sort of setup is usually used against a wall, so they aren't expecting the backsplash to take a lot of abuse. Since you aren't against a wall, be careful in the future.

I don't think there's a need to rough up the mating surfaces, but it can't hurt.

And since you have a perfectly waterproof joint, I wouldn't bother with caulk.