By Mark Clement
I never thought I'd make this comparison, but tile is like siding. In some respects, anyway. You'd think that, properly installed, neither system would let water past. But both do.
The key to jobs that'll last is getting that water out of the system, so it can't damage the house behind it. When you're talking tile, this means you can full-on waterproof the system. And when you're talking waterproofing, you're talking tile membranes.
Also, tile is often installed directly over a young — or huge — concrete slab. Slabs move and can crack over time. If you apply tile directly to such a slab, a crack can telegraph right through the tile — unless you use an uncoupling membrane. We'll talk about both of these here.
Waterproofing Membrane
The word membrane describes three basic systems: a sheet good, a liquid and a urethane. According to Stephanie Samulski of the Tile Education Foundation, even though they're different, all three meet the foundation's requirement for waterproofing.
Sheets. Schluter Systems' KERDI and Noble Company's NobleSeal TS are examples of sheet membrane. You can think of them like house wrap for your shower stall. These woven fabrics are embedded in thinset. Wipe the thinset on with a small toothed trowel, then wipe the fabric on and squeeze out the mortar. They can be used for shower pans and behind wall tile for shower applications. They can also be used on other horizontal surfaces: kitchen and mudroom floors and countertops. KERDI also supplies inside/outside corners for making transitions.
When using the fabric system with a drain, as in a shower, the key to success is tying the fabric into the drain (both KERDI and Noble have a product for wrapping the drain pipe) rather than to trap it inside the tile covering. While you may not have a floor drain in a mudroom (nuisance water there evaporates, by the way), commercial kitchens and bathrooms will likely have this detail.
Liquid and urethane. Liquid products like Laticrete Hydro Ban can be rolled, brushed or troweled onto the substrate — and right up to the drain connection. Aside from the brushes, you're dealing with a single component on-site, according to the company, rather than having rolls, inside and outside corners, and other parts. And you can wipe it up coves and corners with no lap joints. Once you've put it on (minus a 24-hour cure time), you're done. It even cleans up with water, so you can re-use brushes. The stepping-off point for a urethane versus liquid is that urethane is stiffer; you apply it with a trowel.
For nuisance water, say on a kitchen floor, Laticrete Watertight applies like paint, according to the company. You can build it up about 1/4 inch. It dries in two hours.
Crack isolation. Membranes do more these days than keep water off a wood subfloor and/or divert it to the drain. They can also provide both waterproofing and some crack-isolation capabilities — what tile pros call "uncoupling."
Schulter's DITRA is a waffled sheet that provides for independent movement of a slab beneath the sheet and the tile covering above it — key for reducing call backs due to cracking. It can also do double duty as a waterproofer.
Systems like this can also enable tile setters to alter the expansion joints in larger tile floor systems. Normally you have to install an expansion joint in the tile straight above the joint in the slab, regardless of tile layout. With waffle-faced systems, the joint can be altered. Check with specific manufacturers for the exact detailing.
Another approach to crack-isolation that provides waterproofing as you go is Mer-Krete's Hydro-Guard One, a thin, load-bearing membrane composed of a modified elastomeric copolymer. With excellent elongation properties and high strength, Hydro-Guard One provides a 100 percent waterproof membrane coating while limiting the transfer of substrate cracks to the finished overlay. The membrane is installed in a liquid state and can be applied to practically any form or irregular shape (i.e, base flashings, parapets, walls, etc.).
Latricrete's Hydro Ban (mentioned above) also has crack-isolation properties. I like the idea of a two-fer when I use a product but don't go crazy trying to save steps. Make sure any product you use for crack isolation is designed for your site conditions. Check with the manufacturer.
Sound isolation. If sound transference between floors is a cause for concern, check out the sound isolation sheets from companies such as Noble and Laticrete.
Noble's 3/64 inch thick NobleSeal SIS reduces floor-to-floor impact noise sometimes associated with hard surface flooring such as tile and hardwood. Laticrete's peel-and-stick acoustical underlayment also muffles impact noises and eliminates substrate cracks up to 1/8 inch to the finished floor.
The underlying truth
The underlying truth of the matter is that there is a huge universe of waterproofing (remember the thick rubber mat, technically made from CPE or PVC, that we put in shower remodels? It still works.), crack-isolation and sound-isolation membranes — both sheet and liquid/semi-liquid. Some do several things. Some are dedicated products.
The key to finding your way through this universe — and maintaining both budget and production requirements — is to work through the details of your project (a commercial kitchen will have different requirements than a residential kitchen) and then work with manufacturers to spec the right system for the kind of work ahead of you. The good news is that with all the choice, you're sure to find the right one.
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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