new tile floor?

November 20, 2011 9:53 AM

a friend's basement flooded, and the floor needs replacing (wood on a concrete slab). she asks if porcelain tile could be laid in, considering the (remote) chance it could happen again. I think so, but wonder about the contact layer, and leveling over the slab. what would you use? would you seal the edges to prevent water getting in there (freezing/expansion)? is porcelain impervious?
posted by ebesan to home & garden (10 answers total)

One word: grout. It's not impervious, and would freeze and expand, in which case it would probably break apart. But, grout can be replaced/redone.

Porcelain depends a lot on its quality. The better the quality, the (much) more expensive.

Has she considered terracotta tiles? They breathe, and most don't need grout (they're set directly edge to edge). I have a local type, tomettes, in my apartment, a "garden apartment" (half basement on the street side), and they're just wonderful. I never have to worry about them, whereas the grout in the tile that had been laid over them smelled strongly of mold. The odor disappeared when I removed the newer tiles. (Links are to photos, just to show what I mean.)
posted by fraula at 10:08 AM on November 20, 2011

Sure, tile is very doable on a concrete slab, and a much better choice than wood if moisture is a potential issue. Tile isn't necessarily impervious to water, but water doesn't hurt it. If the slab is cracked then she'll want to use a crack isolation membrane between tile and slab, to reduce the chances of the cracks telegraphing through the tile. If her basement slab ever gets near freezing temperatures, she's got bigger problems.
posted by jon1270 at 10:08 AM on November 20, 2011

Yeah, I never put wood on a slab, even in slab-on-grade construction. Before you can put any flooring down, you should let it dry thoroughly and then have a professional do a calcium-chloride moisture test on the concrete slab to see how much moisture is present in the slab itself. This will determine what kind of flooring you can put down.

For leveling the slab, you'd want to use a self-leveling cement. I like Custom Building Products Level-kwik RS. Depending on the size of the room, you might have to pay someone to do it -- 150 sq ft is DIYable with 3 people, any more than that you want to have a large crew -- 8 friends -- or a professional do it. If you put in self-leveling cement, you can also put in a heat mat in any areas where people spend a lot of time.

Regarding waterproofing ... yeah, the tile is pretty impervious to water. ("pretty" is not absolutely, but much better than wood or carpet.) The bigger problem is what grout you use, because grout will indeed gather a lot of dirt and in a basement might show lime effects if moisture wells up under the slab. I'd use something like an epoxy permanently stain-free grout, e.g. Laticrete SpectraLock.

Another solution that might be easier for a basement type area that can flood is acid-etching and staining the concrete slab.
posted by SpecialK at 10:14 AM on November 20, 2011 [1 favorite]

We put ceramic tile in our concrete-slab basement after it flooded several years ago; it had been carpeted previously. The tile has been a marked improvement over the carpet -- no more vague smell of wet dog or mildew -- and I've never noticed that the tile was damp, nor have I noticed any cracking of the grout or tile. We live at the bottom of a hill, with a sort-of swampy area beyond our house, so there's plenty of opportunity for water to seep in, but it's never been an issue. We live in Minnesota, and there's never been a problem with freezing or anything either.

It does get cold down there, though; if your friend goes this route, she might want to consider area rugs on top of the tile.
posted by Janta at 10:27 AM on November 20, 2011

There are some great new vinyl flooring products you should look into. My father-in-laws just had a new house built, and their basement has this great vinyl floor that looks absolutely bomb-proof.
posted by Cool Papa Bell at 10:40 AM on November 20, 2011

I would seal the edges with elasmomeric caulking and lay down some softer tiles
posted by hortense at 12:31 PM on November 20, 2011 [1 favorite]

Have you perhaps considered polished or acid etched concrete? It may sound duller than a tiled floor but you might be surprised at how nice it can look.
posted by munchingzombie at 12:53 PM on November 20, 2011 [3 favorites]

I second the acid etched or waxed concrete floors. A friend has it in their dinning area and it looks fabulous. However I know nothing about the cost, its just very asthetically pleasing.
posted by njk at 2:01 PM on November 20, 2011

Tile will definitely work well. Porcelain is best since it is almost impervious.

Traditional grout, however, is not impervious and will actually absorb any kind of fluid.
At the very least you'd want to seal it with a few applications of sealer, and then reseal it periodically.
Or, you could look into getting an epoxy grout. When I was in sales (spent most of my life in floor covering) I sold a lot of Laticrete's Spectralock grout. It can be a PITA to install, but it works well so long as you (or whoever installs) follows the directions EXACTLY. The only time I ever had complaints was when the installer didn't read the instructions.

Also, as mentioned above, tile can be cold under foot so you may want to consider an in-floor heat system. There are systems available that are rated for wet areas such as showers. In other words, flooding would not be an issue. Unfortunately, I can't remember the brand names.
posted by nickthetourist at 9:43 PM on November 20, 2011

Leveling the slab might not be exactly what you want. It is likely pitched toward a drain somewhere, and actual leveling compound would want to flow towards that and be a nightmare.

I would want to install tile in this case too, but polishing and finishing might be a better option. Or an epoxy garage floor type of coating.

Maybe quarry tile would be an option? That stuff is pretty indestructible.
posted by gjc at 6:18 AM on November 21, 2011