Stopping shower leaks at the source

I'd like to have a word with those of you who are experiencing the blight of a leaky tiled shower.

Maybe some boho contractor jury-rigged that baby, or maybe you did, but the point is, it's distributing moisture faster than a newborn.

Here are some clues that put your shower into the target category. There are visible gaps in the caulking or grout inside the shower. There are pockets of discolouration around the bottom of the shower door. The wall might even be lumpy.

What's happening there is the miracle of capillary action. If the grout or caulking has failed in your shower, water starts soaking into the underlying wall and finding its way to the outside surface of the unit. Then it evaporates. End of problem? Nope. The evaporation actually starts a siphoning effect, where more and more moisture gets drawn through the wall, expanding in a widening bloom of dampness, and encouraging carpenter ants, mould, mildew and rust to throw a housewarming party for each other.

The odds are good that someone, either you or a previous owner, has tried the most popular method of 'fixing' the problem - a coat of paint over the stain. Many of us think of paint as an advanced barrier against our own denial. Does it help to paint over a nefarious stain? Yes! For a week. And then that paint starts to peel, discolour or function as a Petri dish for mildew.

The solution? Stop showering! If this isn't a valid option in your household because somebody, say your spouse, has overly rigid hygiene standards, then I offer these humble suggestions.

• Shower pans are complicated. They have lots of ways of failing. If you suspect that the shower pan is leaking, here's a way to test it. Take the grate off the drain (by removing the screws and pulling it up - sometimes it'll be stuck in a bit of grout). Measure the diameter of the drain hole, buy a shower pan plug (a compression style plug that expands into the drain and gives a positive seal), install the plug, fill up the shower pan to an inch below the bottom of the door and leave it 24 hours. If the water level goes down, you've got a problem that will require ripping out the tile and the underlying shower pan and starting over. My advice? Call a professional and make sure you get their references, because it's really easy to screw up a shower pan installation.
• Failing grout is not usually an issue, but failing caulk is (or utter lack of caulk altogether, which happens when people decide to grout the corners of a shower stall instead of caulking them with silicone-based waterproof caulking. And people decide to do that a lot.) In our shower, it's all grout, no caulk. So that's part of the part of the problem. The grout has to be caulked over, but I have to remove enough grout to get a good seal for the caulk. Normally I would use a grout remover, a small saw with a replaceable tungsten carbide blade. But unfortunately, the grout lines are too narrow to accommodate the tool. So instead, I'll be using a utility knife to hack out the old grout. My favourite utility knife for this type of high-intensity work is the new Irwin utility knife that has a bi-metal blade, which won't break off and lodge itself in delicate body parts.
• After chipping out the grout, remove dust with a stiff brush. Then wipe the area down using a rag dampened with rubbing alcohol, which removes soap scum and residue and evaporates really fast.
• A reminder; you want the walls behind the leaky tile to be thoroughly dry before you seal, so make sure no one showers in the offending stall for at least a week before you start the repair. (It pays to plan this repair for warm weather when you can hose down offending relatives who haven't showered in a week.) If you don't give the stall enough time to dry out, you'll seal the moisture into underlying walls and framing, and it will rot, making for an even more irritating and extensive repair a few years from now. For faster drying, set up a heater or fan in the shower to drive off accumulated moisture.