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Grouting Bathroom Tiles

After the bathroom tile has been properly bedded into the adhesive and allowed to cure, it will need to be grouted. Traditional portland-cement-based grouts are now available with additives like latex, acrylic, or epoxy that make them more flexible and less likely to crack. Joints narrower than Vs in. need an unsanded grout, while joints Vs in. and larger should have a sanded grout to add strength and reduce shrinking. For my money, though, I think that it is hard to beat a 100%-solids epoxy grout, such as Latapoxy 210 (from Laticrete International, Inc.). While it doesn't make grouting (a job I'm not particularly fond of) any easier, the resulting grout joints are remarkably flexible, durable, stain resistant, colorfast, and seemingly impervious to the problems that sometimes plague conventional grouts, like cracking and mildew growth.

Before doing any grouting with either a traditional portland-cement-based grout or with epoxy grout, make sure that grout joints are cleaned of excessive adhesive and that any spacers have been removed. Uniform joint depths are critical for color consistency with portland-cement-based grouts. Vacuuming thoroughly afterward will clean out the debris that can get stuck in the joints. Keeping the bathroom tile slightly damp and at a cool temperature (between 65°F and 75°F) with a sponge or mister and clean water will keep portland-cement-based grouts from drying out too quickly and make grouting easier. Epoxy grouts, on the other hand, require a bone-dry surface. For both types of grouts, proportioning, mixing, and slaking instructions should be followed carefully before starting to pack it in.

Using Epoxy Grout On Your Bathroom Tiles

My first experience with epoxy grout was a disaster. I assumed that I could use the same softrubber grout trowel that I'd used with portland-cementbased grouts, that I could grout at the same pace and with the same techniques, and that I could mix up and use an entire batch at once. I was wrong on all counts.

Instead of working like, well, grout, the stuff was like a sticky peanut butter, and my trowel wasn't stiff enough to cut away excess grout after the joints were packed. The realization that this stuff was epoxy and wouldn't easily clean off the face of the bathroom tile once it cured made me panic and concentrate all the more on getting every last bit off, which made my progress even slower. About one-quarter of the way through the job that I'd mixed an entire batch for, the epoxy began to set up. Frustrated, exhausted by the frantic pace, and blinded by sweat pouring into my eyes from the 90°F heat, I watched as three-quarters of a batch of very expensive epoxy grout solidified in the bucket.

But I did learn some lessons from that experience. Now I mix small batches of epoxy grout at a time, keep several buckets full of clean water and a big stiff sponge for cleaning, use a stiff rubber trowel for grouting, and have on hand a good abrasive pad or two.

After a small (10 sq. ft. or so) area of bathroom tile is packed, I'll pull away the excess with the trowel held almost perpendicular to the bathroom tile and at about a 45° angle. I don't worry so much about imperfect joints or excess grout at this point; I know that in a few minutes, after the grout has stiffened, I'll be going over everything with an abrasive pad and water. The abrasive pad helps to scrub the bathroom tile clean, and water lubricates the epoxy, turning into a slurry that won't reattach to the firmer epoxy already packed in the joints. The pad needs frequent rinsing in one water bucket, and after one area has been scrubbed I'll clean off the excess epoxy and foam with the sponge, rinsing frequently in the other bucket of water.

Shaping the joints is done mainly with the pad, though I also try to clean them up with the sponge as I'm cleaning everything off. Using a cheap sponge is a mistake because it will start to deteriorate and leave fibers in the grout, and a flimsy one won't bridge the joints well. After the grout has hardened, there will be a haze that can be cleaned off with mild household detergent and water and a sponge. The grout may still be slightly sticky, in which case protect it from traffic until it is fully cured.