I had the same concerns when I did my kitchen, but was reassured that once it is sealed it is not a problem. I do not like the look of a different material above the slide-in range and since my granite is very dark, I didn't want it as a full backsplash. I LOVE LOVE LOVE my tumbled marble backsplash. I sealed it with one coat of 511 impregnator and Vioila, nothing penetrates. Here is my picture, which I am sure everyone here is sick of seeing already! Susan

I'm assuming the weight is factored in. We are using a popular, high-end kitchen designer. Then again, is there an issue with using a slab? The kitchen plan has two sides/walls with an island - so an L shape. The side with the range and upper cabinets will be completely covered by the marble slab but the other side/wall of the kitchen, which is directly across from the island, doesn't have cabinets and we would only be extending the marble up to be even with the end of the cabinets on the range wall. I guess one of my issues is I don't know if it is worth in to spend that much when the main accent wall is at an angle, rather than in direct view of the island seating and dining room table. Also, I think I would be saving a ton by using even a high end marble subway tile.

@wannabath - I don't know what a "perfect" tile install would be but my very skilled installers certainly didn't make me sign any waivers with regard to my marble installation. What they did with the help of my designer was to lay out the tiles so that they created a very nice variation. This is what my wood floor installers did in terms of taking the time to make sure that the boards were appropriately placed so that they appeared "random". They were just out last week because I am having them tile my balcony and spent a LONG time examining the tile samples and conferring with the GC and my designer to determine exactly how the job would be done to get the results I wanted. I spoke to my designer since I hadn't been onsite when my bathrooms were done and she said it was standard operating procedure for the tile setters to have the sample tiles available in order to evaluate and determine the best way to proceed. They went out on the balcony to look at the site conditions which was especially critical since I need the appropriate slope AWAY from the door and towards the weep holes so that the balcony has appropriate drainage.

@SJ McCarthy: Lots of questions so I am going to break it down: "OK...the 'sealant' isn't a sealant. It is old glue from vinyl tiles. Has it been tested for asbestos? How old were the tiles that were taken up? Do you have photos of this glue-mess?" Whatever the "sealant" is, it doesn't allow water to be absorbed and the 2-3 installers I spoke with about gluing wood to it, all said it needs to be porous. Bostik also said it needs to be porous. I'm guessing the sheet vinyl was original to the house. It had 65% asbestos in the fiber backing. I had it tested. Tyvek suits, p100 respirators, hepa filter and wet scraped it. It still left a ton of residue so we used a mastic remover. Nasty nasty stuff that was not meant to ever be removed. House was tested for fibers and is considered safe. The slab looks great now, I considered just finishing it and having an industrial look, but that isn't very popular in my area so would influence resale. The glue down floor is the most expensive wood install we have. Your slab is one of the old one's that is almost guaranteed to have moisture issues (builders started using moisture barriers under the slab in the mid 1990's). Before you think about 15 years down the road, I would pay for the moisture testing of the slab (in-dwelling probes are your best method of testing the moisture level already in the slab). This can be done now so that you can make decisions later. There is a moisture barrier under the house because I saw it. The floor was jackhammered in a couple places for drain work and there was a very nice, black, intact moisture barrier present. I made sure to put the moisture barrier back, best I could, before the floor was closed up. The adhesives are expensive. They have to be. You would have to use one of the most expensive glues on the market = $2-$3/sf. That's ONE of your mark-ups. The other is the labour which is, another $2-$3/sf. Labour costs are roughly 1/2 the price of builds. Human sweat and KNOWLEDGE come at a price. The cost you were quoted for labour (on the glue down) is completely in line with a knowledgeable human doing it properly. Your installer isn't gouging you...s/he is in-line with the cost of his knowledge/time it will take to get this done properly. I agree. I don't think I am being gouged. The total cost of materials + install of $4.50/sf is very, very low. The preparation is going to be more than the cost of the wood. Preparation must be paid for. With a situation like yours (left over glue on a slab that needs flattening) is going to be $2-$4/sf. I would guess high. Removing the glue is a b!tch! Yes it is going to cause dust. That's what happens when dealing with old things like glue over slab. The cost of materials to float the floor per square foot are $.50 quiet walk, $.50 floor prep, $1.70 wood flooring, $1.80 labor. It's a DIY click lock floor and I asked for them not to glue it on the edges. I HIGHLY recommend you speak to your installer (who sounds like s/he is one of the one's who knows what he's doing) about the cost of the preparation. Labour to install a floating hardwood (there is glue that is added to the joints of every plank) should be $2.50-$3/sf (includes the glue). He charges $2.25 to install wood floors. This isn't the prep work or the finishing work. The labour for the concrete prep is a different cost. I would ask about that. This was a little different, his number changed a few times for this which made me concerned he isn't as proficient in this area since he usually works new construction. His final number was $.50.