Anyone, anyone? I'll give a little bit of background info. The tub deck was framed by my contractor, about 1-1/2" lower than the undermount tub. My tile installer then installed paper, lathe and mud up to the height of the rim of the tub and leveled the top. Prior to installation of the marble top, we discussed with the marble fabricator the method he would use to install it. He assured us he would use a layer of thinset and then set the marble on top of the tub deck. Instead, he used wood shims and placed the marble on top of them, and siliconed it in place. The wood shims have raised the marble up about 1/4" off of the tub deck and since he used very few shims, there are large areas where the marble has absolutely nothing underneath to support it.

Can this be fixed without removing the marble? If it needs to be removed, is there a way to do it (gulp) gently so it won't break?

With slab, it's usually set with silicone caulk, but not to the point that it's sitting a 1/4" off the tub. Let me ask you-- is this 2 or 3 cm stone?

As always, thanks for your help Bill. It is 3cm stone. Should the wood shims have been used? The tub deck was already level before the marble installation and had a nice solid mud base. (Even if it wasn't level, should wood shims ever be used for this?) Is there anything we can do to salvage the marble without it remaining at its current height? If it stays at the height that it is now, there will be a huge visible caulk line around the inside of the tub where it meets the marble. The fabricator said he will have to use white silicone there instead of the clear that he normally uses. Presumably, this is to hide the shims which are visible if you are at eye level with the marble (i.e., sitting in the tub). They still have my second choice slab just in case something went wrong with this one, but are supposed to make the vanity top from it. What should we do? Also, would anything have been wrong with using thinset instead of the silicone caulk that you mentioned? Thanks Bill.

The wood shims were most likely used to level the stone, wo they'd have a good meeting at the seam. Being this is 3 cm stone, you should be fine. You'd have to TRY yo break it. This is why I asked you about the thickness.

As for using thinset instead of caulking, no, I don't see any problem with it, but silicone IS the industry standard for setting slab stone like this over woodframe.

Thanks Bill. There is actually some flex to the marble in at least one spot where it is unsupported for almost 12" and I'm concerned it will crack if someone sits on it (it is at the front edge of the tub deck). Also, is there anything we can do about the huge white caulk line we would end up with?