Caulking & Regrouting on San Juan Island

This page is a narrow one on purpose: the sealant and the tile surfaces in wet rooms. Cutting out failed caulk at tubs, showers, counters, and backsplashes and putting a proper bead back. Regrouting tile that has gone soft, cracked, or dark. Replacing a cracked tile. Resealing cement grout and natural stone. It is surface work and sealant work. It is not plumbing, and there is a hard line further down this page about where I stop.

The reason it matters more here than in a dry climate is the way island houses are used. A second home closed up from October through May holds high humidity for months with no air movement, and mildew does not need a leak — only damp and stillness. Guidance for keeping mold out of houses lands on holding indoor relative humidity below about 60 percent, which is not what happens in an unheated, unvented island bathroom in February. Add the bathrooms in older cabins with no exhaust fan at all, or a fan ducted into the attic instead of outside, and you get the pattern I see over and over: a shower where the caulk has gone black, the bottom two grout joints are crumbling, and nobody has been in the house since Labor Day.

The bead itself is misunderstood, so it is worth explaining what it is doing. Where tile meets a tub, a shower pan, a countertop, or another wall, the industry standards call for a flexible sealant rather than grout — ANSI A108.01 section 3.7.4 and the TCNA Handbook method EJ171 require movement joints at perimeter joints and at changes of plane, meaning inside corners. Grout is rigid cementitious filler. It has no stretch in it. Every one of those joints moves, because a tub full of water deflects, a countertop moves against a wall, and wood framing in a house that swings from soaking wet to dry every year moves the most of all. Grout a corner and it cracks; that is not bad luck, it is physics. So the corners and the perimeters get a flexible sealant meeting ASTM C920, generally a 100 percent silicone in a color matched to the grout, and the flat field joints get grout.

Doing it properly is mostly about removal and patience, and it is the part that gets skipped. New silicone will not bond to old silicone, so every trace of the old bead has to come out with a blade and a scraper, not be smeared over. Then the joint gets cleaned and treated for mildew, then it gets genuinely dry, which in a closed-up island house in winter means heat and air movement first and sealant second. I mask both edges, run the bead, tool it once, and pull the tape. On a tub I fill it with water before I seal, so the joint is loaded in its worst position and the cured bead is not being stretched open the first time someone takes a bath. That single trick is the difference between a bead that lasts eight years and one that splits in eight months.

Regrouting is the other half. Grout removal is done with an oscillating tool and a carbide blade, cutting the joint out cleanly without chipping the tile edges, which is slow work and the reason regrouting a shower is a real job rather than an hour. Then the joints get vacuumed, the tile gets cleaned, and new grout goes in, matched as closely as I can get to what is there. Where the grout is in a shower floor or a heavily used bath I will often recommend an epoxy grout instead, because it does not absorb water and does not need sealing, at the cost of being harder to work and more expensive. Cement grout in a wet room gets an impregnating sealer afterward and needs it renewed every couple of years, which is a good line item on a property care visit.

Be clear-eyed about what regrouting does and does not do. Grout is not the waterproofing in a shower and never was — it is a permeable cement filler, and the real water barrier is the membrane or pan behind and beneath the tile. So new grout makes a shower look right, slows down surface absorption, and stops the crumbling. It does not repair a failed waterproofing layer. If the water is already getting past the tile, regrouting the surface just hides the symptom, and I will tell you that on the first visit instead of taking your money for the pretty version.

How I read a wet room, in the order I check it: whether the mildew comes straight back within days of a proper cleaning, whether any tiles sound hollow when tapped or move under a thumb, whether the grout is soft or the joints are wet a day after the shower was last used, whether the floor is spongy at the curb or the threshold, and whether there is a stain on the ceiling or in the cabinet below. Two or more of those together mean the problem is behind the tile, not on it. There is also a common island version with nothing to do with the shower at all: condensation on cold tile and a cold exterior wall in an unheated bathroom, which reads like a leak and is really a ventilation and heat problem.

Now the line, and it is not negotiable. I hold a Washington general contractor registration, not a plumbing certificate. I do no pipe, supply, drain, or waste work, no valves, no shower pans, and no fixtures — I do not pull a toilet, reset a sink, or touch valve trim, even to get at a joint. If the water is getting in behind the tile because a shower pan has failed, a valve is weeping inside the wall, or a drain connection is leaking, that is licensed plumber work and I will say so plainly. What I do then is the pattern I use everywhere on this site: photograph and document what I found, call you, get a licensed plumber booked, and meet them at the house so nobody is trying to explain an island bathroom over the phone. Once the water is fixed and the assembly is dry, the sealant, grout, tile, and any drywall repair are mine.

Two other jobs live on this page. Cracked and loose tile replacement, where the difficulty is never the setting but the matching — island bathrooms are full of tile that went out of production twenty years ago, so before I order anything I look for a leftover box in the crawlspace or garage, and failing that I steal matching tile from a hidden spot like behind a toilet or inside a closet and put the new tile there. And countertops: the joint where a laminate top meets the backsplash, the perimeter of a drop-in or undermount sink where the sealant has failed and the substrate is starting to swell, stone seams, and the impregnating sealer that natural stone needs and rarely gets. A single cracked tile in the middle of a floor is a tile. A line of cracked tiles running across a floor is movement or deflection underneath it, which is a floor repair conversation before it is a tile conversation.