What's behind damaged bathroom tile?

HOME WORK

February 05, 1994|By Karol V. Menzie and Randy Johnson

One day you happen to notice a piece of bathroom tile is loose. Just one, looks like a little crack in the grout. . . . Well, actually, the tiles next to it are a little loose too. . . . Maybe half a dozen altogether. Nothing to fixing that, right? Just pry off the old tiles, slap on some new adhesive, stick 'em back up. A simple Saturday afternoon job for the do-it-yourselfer.

Not necessarily.

Tile adhesive is virtually never the problem when a tile comes loose. Instead, loose tile is an indication that some component of the tile-backing system has failed, allowing water to get in and destroy the bond.

The most obvious culprit is the grout. It can dry out or crack and let water seep in between the tiles. However, the grout may have cracked because something behind it has gone wrong.

In fact, neither plaster nor drywall is a good surface to back tile. If the tile and grout fail to protect it, or if moisture gets in from some other source -- a leaking pipe or faucet, window or roof leak that gets inside the wall -- both plaster and drywall will crumble. Standard drywall is not water resistant, and unless it's been specially sealed, neither is plaster.

Plaster clings to its lath backing because of its "keys" -- the plaster that oozes through the gaps, over the backs of the lath strips, and hardens in place. Water damage, settlement and vibration (such as that from passing buses) can break off the keys. Once the keys are gone, it's only a matter of time before the plaster fails.

Bathrooms are amazingly damp places. A simple shower can pump gallons of moisture into the air. In a sense, the tiles are a thin line between walls and disaster.

So when tiles are loose, it may require a fairly complicated procedure to fix them. Some fixes may be so extensive they knock the bathroom out of commission.

Tile needs a solid subsurface. If the subsurface is damaged, the tiles will have to be removed and the subsurface repaired or replaced. Just removing the tile may damage the subsurface -- and the tile itself may not be salvageable. If the tile is old, you

may not be able to match it. If a good match is important, you may have to remove all the old tile and replace it. And even if you can match the tiles, you may not be able to match the old grout: The patch will always show.

Three case histories illustrate some of the problems in tile repair.

* Some time ago Randy worked on a bathroom in a 150-year-old house in West Baltimore where dampness had invaded the plaster behind the tile about three rows high just above the tub. When he got the tile off, the wall behind the tile was actually slimy. He took out all the bad plaster and used a fan and a heater to dry the space. Once it was dry, he was able to patch it with a fast-drying plaster. Then he primed and sealed the wall. He was able to replace the old tile with a close match. Then he cut down all the old grout and regrouted the entire bath, so it would all match.

* In another project, changing the layout of the bath is going to lead to re-tiling part of the tub wall. The new owner of the house wants to install a larger tub than the one used in an earlier rehab. The existing tile is in pretty good shape -- which means getting it out will inevitably damage the wall.

The solution: Cut out the tile wall back to the framing; install the new tub (a properly installed tub is fastened into the framing; failure to do so leads to cracks and gaps in the grout around the tub edge); replace the drywall; re-tile with matching tile and regrout the area.

* Karol's old bath has a lot of tile problems, not the least of $H which, from her point of view, is that it's ugly. It's also no longer fastened to the wall behind the tub, and it's bulging in a number of other places. This is certainly the result of water damage, some of it from "fixes" by previous owners.

All of the old tile will have to be removed and the surface behind it replaced -- not with new drywall, but with cement board, a relatively new product. It's installed like drywall but is more impervious to moisture. Then new tile can be installed. Since the tile goes all the way around the bath and nearly to the ceiling in the tub area, this is a big project that will make the house's sole bath inconvenient, if not impossible, to use for a while -- which is why it hasn't been gotten to yet.

Another problem area for tile is floors. Floor tile also needs a solid subsurface. It's usually plywood -- and plywood is subject to the same ills as plaster or drywall. Water, settlement and vibration can damage it so badly it has to be replaced.

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