By Mark Clement
We all know that hollow feeling we get when we pick up the phone and hear the voice of a disappointed customer.
Fixing a nail pop in drywall or tuning in a door that won't shut properly is one thing, but when the call is for cracks, hollows or grout failures in a tile floor, backsplash or shower surround, that's a whole other kettle of fish.
Here's a top 10 list of things to do right, look for — or look out for — compiled with the help of Stephanie Samulski, a union-trained tile setter and instructor at The Ceramic Tile Education Foundation.
(Side note: The cool thing about Stephanie is that she's the real deal; she was grouting tile while we talked through this list. Now if she comes to my area to teach a class, you can bet that's the kind of teacher I want.)
1. Uncoupling membrane. Compressed cycle times (what some builders call fast-tracking) can lead to installing tile too soon over green (or young) concrete slabs. While installing tile over a cured slab is fine, young slabs are still moving (shrinking, to be exact). Tile doesn't do well over a moving substrate. The key to maintaining production speed — and setting tile — is to use an uncoupling membrane between the slab and the tile. When you're buying the actual membrane, make sure that it is approved and warranted for this purpose by the manufacturer.
2. The right adhesive. You might think that all thinsets are the same, but it's not true. The marketing language on the packaging might indicate that they all do the same thing, but as with anything in life, you have to look a little deeper. Check the data sheet. Look for bond strength; suitability in wet areas (you don't want a low-end adhesive for tiling a hot-tub surround or walk-in shower room); and flexibility. You need a more flexible adhesive for installing tile over wood joists and plywood (say, in a large kitchen remodel) than you do for installing over slab-on-grade.
3. Cure time. Don't grout too soon because you're in a hurry. Thinsets need time to dry properly before they can accept traffic. Latex-modified thinsets take more time to cure than unmodified mortar. If you've installed a low-porosity tile like porcelain, it can take even longer. And when you do grout, be careful about dragging heavy buckets of water across the face of the tile. You can catch an edge with the rim of the bucket and loosen a tile.
4. Big tiles. If there's a trend that's been moving through the tile trade for a while, it's the use of larger and larger tiles — 12"x12" and up. Because they cover so much surface area, the thinset beneath them takes longer to cure. Be patient. Schedule accordingly.
5. Backerboard. Despite the fact you want to screw it down and start laying tile immediately, backerboard manufacturers (whether it's cement, fiber cement, foam or gypsum, among others) require bedding boards in mud. This helps isolate the stable backer (and tile above it) from movement in the joists and subfloor below. It also mellows out dips, lips and humps in the subfloor. Prevent voids on the bottom side of the backer by making sure there's enough thinset along the entire back of the board.
5. Spacing backers. While you can butt gypsum and foam-based backer material (there's a little give), it's a recommended practice to space cement and fiber-cement boards about 1/8 inch. You also should mud and tape the joints. Doing so creates a monolithic surface that acts much like the big ol' honkin' mortar beds of old.
7. Setting tile. Make sure you get proper thinset coverage on the back of the tile. Eighty percent coverage is good. You want to bump it up to 95% in wet areas. It's a good idea to install and remove a tile every 20 minutes or so to make sure you're getting the needed coverage. The key is to wipe out and comb the thinset carefully — especially in corners — with the proper notched trowel. Coverage is especially important as tiles get bigger. If you hear a hollow sound behind the tile when you knock or walk on it, it's a sure bet there's not enough thinset behind it.
8. Lippage. While I find "lippage" a cool-sounding word, it's something you don't want. Lippage means that tile tops are not set flush with each other — and this is something that can easily be missed while installing. The best thing to do is carefully feel the union between tiles with your fingers and make sure they're as flush as possible. Check all the way around a tile, too. You want it flush on all sides. No lippage!
9. Layout. Cosmetically, you want tiles to lay out so that you have equal tile widths on each end of a room or hallway. If you don't do this, but otherwise install the job right, the tiles aren't going to jump off the floor or wall. But they could look better. Also, when you meet a moveable object — a wood base molding, a cabinet or some other trim detail — do not grout this joint. Use a flexible caulk. Best practice is 100 percent silicone or other caulk that ASTM C920 specs for elastomeric joint sealants.
10. Mixing grout. Grout should typically be stiff and work your forearms as you wipe it in. Mixing it too wet leaves it porous, which means that it'll accept stains and dirt more easily. If you add water to re-temper a big bucket of grout as you move across the floor, it'll change the color subtly. Not good. The way to figure out the best consistency for the grout you're using is to mix one bag to manufacturer specs so you know what the right mix looks and works like. Then eyeball it from there with smaller batches.
If you keep these 10 points in mind with every tile installation, you'll turn out better jobs and have happier customers — and less of that hollow feeling.
Mark Clement is a remodeler and author of The Carpenter’s Notebook and The Kid’s Carpenter’s Workbook, Fun Family Projects! Check out his books and current projects at his new website.
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