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Having seen signs of leakage years ago, I caulked and double-caulked the shower door, to no avail. I have never seen any leakage around the door, though. The shower-door track bottom has drainholes; I made sure to leave those free-flowing, thinking if these were blocked it might allow leakage.
I have checked all the caulking in the shower (base and corners), and it is in good shape, and so is the grout. I remember you previously mentioned windows in showers are a big contributor to leakage. But this is not an issue, as there is no window.
I'm pulling my hair out trying to figure this leakage thing out. When I get underneath the house in the crawlspace, I don't see leakage or rot.
Do I need a new shower?
A: Contrary to popular belief, grout is not waterproof. Common sense would tell you that if it is in a shower, it would be. But it isn't. Moisture passes through grout.
So when water penetrates the grout, where does it go? Well, it is now between the back of the tile and whatever material is beneath the tile.
In a home built before about 1963, likely the tile is set in cement-based mortar. In these cases, the mass of the substrate absorbs the moisture and keeps the tile securely adhered. Rarely do these old-school showers have problems (other than ugly tile colors).
Homes built between about 1964 and 1992 would generally have tile glued to green-board "water-resistant" drywall. These soften relatively quickly (10 years) and turn to mush if used regularly, loosening the tiles and cracking the grout. They have created so many problems that drywall is now illegal to install in a shower (in an unusual but welcomed regulatory move by building authorities).
Newer showers are backed with cement sheets, with trade names such as Hardibacker or WonderBoard. With troweled-on coating between the tile and cement board, these installations have proven to work well so far — and be a vast improvement over the chronically poor showers of the not-so-distant past.
Getting back to your shower specifically, the top of the Fiberglas pan has a lip (more correctly called a nailing flange) behind the lowest horizontal caulking line, where tile meets Fiberglas. This flange prevents water from running back into the wall behind. Tubs built since the 1950s also have this flange. But we are accustomed to caulking between the tub and the tile, since older tubs didn't have this flange. Caulking kept water from sneaking over the tub edge and into the wall on the older ones. While caulking may be aesthetically pleasing, it is actually counter-productive on newer, flanged tub and showers. I am NOT advocating removing your caulking!
So now water has penetrated the grout, and gravity has pulled it down to the flange, where it is stuck between the caulking, the flange, and the tile. The water builds and can go nowhere but laterally along the flange. As it travels, it eventually comes to the front edge of the shower pan, where gravity pulls it down to the floor.
Here is where you are seeing the loose tiles on the wall outside the shower, and leakage in the floor, but not actually seeing any water. The leakage is actually behind the tile.
Shower-pan manufacturers have addressed this by inserting weepholes into the corners of the shower pan. Other shower pans may have "weep-humps" rather than actual gaps — same function. In either case, no caulking should fill the gap, as the weeps allow water to drain back into the shower before it spills into the wall outside the shower.
Weeps are a great idea, and they work on a pan so equipped, but reliance on a weephole is like closing the barn door after the horse has escaped. Preventing leakage through the grout eliminates the need for weepholes. And grout can be sealed using grout sealer. Sealer helps lessen moisture penetration, makes the grout easier to clean and prevents mold buildup. And it is so cheap and easy to apply.
Tap and lightly push on the tiles inside and outside your shower. Where they sound hollow, move or have cracking grout, you have damage to the substrate (drywall, in your case).
The affected tiles need to be removed, a repair performed beneath and the tiles reattached and grouted. Then clean and seal your grout.
The lowest horizontal portion of the shower door track should be caulked only at the exterior. Caulking along the interior will also will help trap water, which can again run laterally into the wall at the ends of the door track — despite your open track weeps.
Darrell Hay answers readers' questions. Call 206-464-8514 to record your question |
