Tile work through the ages: the good, the bad, the leaky

During a discussion of grout cleaning last week, I announced that tile showers installed between the mid-1980s and the early 1990s had an obscenely high rate of failure. Let me explain further.

In the good ol' days, tile was set directly into a cement base. Tiles were installed by skilled labor, individually spaced and grouted. The cement base held each tile firmly. Quite a few of these installations from as far back as the '40s, and '50s are still truckin' with very little maintenance, even after suffering tile cracking.

Beginning in the mid '60s, we discovered a quicker approach for a lot less money — simply glue the tiles directly to water-resistant green-papered drywall with some of the promising new mastics.

Contrary to popular belief, grout is not waterproof, so moisture eventually got to the drywall. Wet drywall has the consistency and structural integrity of oatmeal in a baby's spoon. The wall weakened, the grout cracked, and more water got in. Fifteen years was about the life of these showers with consistent use.

Fast forward several years, and we saw the advent of weakened grout mixtures due to environmental regulations. Relatively thick grout lines disappeared, replaced with stacked and backed tiles in 4-by-4-foot sheets with no grout spacers between. Thin grout lines required further watering down of the grout to get it into the minuscule spaces between tiles.

Non-sanded grout became the standard, as sanded grout would literally not fit into the openings (it requires a 3/16-inch gap). Sanded grout is much more durable. Modern non-sanded grout is so poor that you can literally scrape it out with your fingernail. I do this frequently to eliminate unsightly shrinkage cracks.

In the late '80s, tile setters told war stories of bidding large apartment jobs at $20-$25 per shower for labor, and making good money at it! Ten minutes to glue the precut and backed tile, come back later the same day and spend ten minutes grouting. One after the other. Each and every one of those showers has been replaced or is leaking into the unit below.

Vapor barriers inside walls made their debut in the '80s. A few months later — after the glued tile fell off the drywall — they realized what a huge mistake these barriers were.

The early '90s saw the beginning of widespread cement board (trade names such as Hardi-backer, Wonderboard, Durock) usage behind tile showers. The Uniform Building Code, in an unusual step, outlawed glue-on tile over drywall.

The challenges facing owners of the newest generation of tile showers have to do with the lateral transfer of water and sealing of grout. Moisture passes through grout joints, and down to the flange at the rim on the tub or fiberglass shower pan (mud-set shower bases excluded from the discussion). As the water cannot travel into the wall, and cannot return to the shower, it is forced sideways, eventually finding its way past the rim, behind the outer wall and under the floor outside.

Those conical circles under the carpet, loose tile on the wall outside the shower, stained grout outside and bubbling wallpaper are a result of lack of operating weepholes and/or not sealing the grout. Weepholes or weepbulges are put in most fiberglass shower pans near the edges. No caulking and no tile should ever fill the cavity. This allows water to re-enter the shower before it can go elsewhere and cause damage.

The necessity for weepholes is lessened when the grout is sealed. I frequently get requests from readers regarding epoxy grout, thereby negating the need for sealing. You will have a difficult time finding even a professional who will use epoxy grout in a residential setting, because it is so difficult to work with. Epoxy grout does not allow repairs (it melts into the tile like a glue), can cause injuries to the installer (sores and kidney ailments) and is not as consistent as cement grouts, making for a visually less appealing finish.

Epoxy grout sealers, which come in different colors, are among the best products available and are generally considered permanent. They are impenetrable to acid and water when dry. But they won't penetrate well with non-sanded grout.

Some tile professionals may recommend simply replacing non-sanded grout after 10 years when it disintegrates. I have seen good results (measuring moisture levels over time) with some acrylic, latex and silicone sealers despite the fact that they need to be renewed every six to nine months. Penetrator is one brand several of my clients have been pleased with. Polyurethane sealers are available, although I have no personal experience with it. A solvent- or oil-based sealer likely is going to last longer than water-based.

Darrell Hay answers readers' questions. Call 206-464-8514 to record your question. Or e-mail dhay@seattletimes.com. Sorry, no personal replies.