Not knowing the climate makes it difficult to give useful advice but, in general, disguising the nature of an exterior material rarely works for long. Dissimilar materials in direct contact exposed to the weather move differently and eventually separate unless that movement is provided for (ie, no direct contact as in a brick veneer cavity wall, etc.). Even real brick in contact with concrete will eventually have to be rebuilt. Stone is best over concrete. Stick something on and be prepared to replace it when the edges and corners separate and start to look bad.

Thanks for the additional posts. The grout used in the original installation and the "patch" jobs was the Congoleum Duraceramic premixed grout. A family member suggested that maybe humidity was a problem. We live in an older house (about 90 years old), but the flooring is installed in a newer addition. Plus, we have a humidifier installed on the furnace system. Any thoughts? Has anyone had problems with the grout cracking that was successfully corrected and how? I'm worried that the original grout might just continue to crack and crumble under a new layer of grout as suggested by the Congoleum rep. Need to check out the flooring inspector directories suggested to see if any are close or have experience with this product?

Are you also replacing the treads on the stairs? If so, will the risers be the same? Standard step height is usually 7.5 inches, but 1-1.5 inches of that will be the tread. This leaves 6-6.5 of actual riser. Of course, this varies based on local code. I'll take some pictures tonight of any areas where they had to vertically trim down tiles (it wasn't much). Depending on the design, I think trimming half an inch off of the top and bottom of your tiles would be too much and would be difficult to make consistent and vertically centered. I think, if you have 7 inch risers, you'd be better off using 6 inch tiles and adding a trim piece to the top of the riser, underneath the tread. A simple quarter-round or cove would work. Here's a picture (not mine) of a cove moulding underneath the tread. This will reduce the vertical height available for the tile.

Carey, it would not be Corian quartz (Zodiaq), it would be Corian solid surface, which is acrylic (?) Joseph, I have been going a little Corian crazy in this house: custom shower receptor, custom vanity tops with a short narrow coved edge that blends with the tile thicknesses, custom toilet paper niche that fits into the tile layout, custom coved shelves that fit exactly into the tile layout, two waste baskets, a "tile" for one specific spot for which no trim tile existed, shelves for the medicine cabinet with holes in them for tooth brushes and razors, and a door to the cat's tunnel complete with "grout lines" and an integrated finger pull, since the cat tunnel in the bathroom also fits into the tile layout. So I am a little obsessive (thinking of a Corian hood for the kitchen) and the fabricators have gamely made everything I have designed and thrown at them. I have an open railing (not code compliant) that is wood (white painted and capped with a piece made of clamshell and pole railing. It needs to redone and fitted with something like mesh in the opening and I will probably make this out of metal for "object integrity" but capping it with Corian and making matching handrails out of corian (Glacier white) and topped with Avonite Fondant (which is the only solid dark brown I can find) would be great and play into my obsessiveness, especially if they could make curved pieces which would probably be out of budget.