Article 6

Because we’re in the business of fixing tile and stone problems, we get calls pretty much every day from folks who have issues with tile in wet areas like showers. Some problems we can fix, using regrouting, colorsealing or minor repairs Marble Polishing.

But unfortunately, many times the problem was created the day the shower was built – incorrectly. The problems range from water leaks to cracked tile and grout, anywhere from an annoyance to a very expensive replacement.

Why listen to us on this?

For many years we used to build showers, installing stone and tile with 4 crews working all over Eastern Massachusetts and Southern New Hampshire. So frequently when we see a tile cracked or a grout line crumbling, we know how easily that problem could have been avoided during the initial build.

And now we don’t offer any tile installation anymore, so we have no ‘dog in the fight’, so to speak. If we recommend you tear out your shower and build a new one, it’s because we believe it’s what you need, and we don’t make any money from that.

In the metro Boston area, there are some very talented tile installers who do beautiful work. But in some cases, they know how to cut and install beautifully but they aren’t as skilled in the surface prep work that needs to be done beforehand. So, their beautiful work may end up being ruined and must be prematurely replaced due to water damage and structural issues.

The average homeowner doesn’t know how to select a good tile installation contractor and even some general contractors aren’t sure if their tile subcontractor is doing the surface prep and installation technique that’s the best practice.

The purpose of this checklist is to hit the high points that can cause damage if done wrong. It’s not an all-encompassing list of every mistake one could make in building a shower. Just the most common ones that we see a lot.

The checklist is not designed to harass the contractor at every turn by analyzing every box of screws he brings on the jobsite. That could easily cause an unproductive temper flare up.

Instead, consider using the checklist before selecting a contractor. You could simply forward the checklist and ask his opinion on it. A minor disagreement or adjustment probably isn’t crucial, but if a tile contractor you’re considering disagrees with most of the list, you’d be better off saying goodbye before spending any of your hard earned on him.

Note that this list doesn’t address the more complicated stall shower construction, but some of the points are the same.

CHECKLIST FOR BUILDING TUB SHOWERS

1. Before demolition begins, implement dust control measures. All demolition generates dust, so proper containment is essential from the start.

2. Cover the tub drain opening with tape before demolition to prevent tile fragments from entering and potentially clogging the drainpipe.

3. Inspect the studs after removing the old tile and backerboard or during new construction. They should be straight, rigid and stable. Standard installations use 2×4 studs at 16 inches on centers with reinforced corners. Test by physically pushing on them to check for movement or ‘wiggle’. Loose studs can cause future tile and grout cracking. If studs are damaged, improperly spaced, or flexible, reinforce them with additional framing. Some tile contractors may complain that they don’t do carpentry but reinforcing them at this stage is worthwhile even if it causes problems with the tile contractor’s schedule.

4. Right after demolition is the ideal time for a plumber to change the valve and inspect the pipes. With no walls in the way, he can identify potential issues easier.

5. Use only cement board products for the backerboard layer. Regular drywall or “greenboard” without very good waterproofing are guaranteed to fail for wet areas. Even if some building standards allow drywall in a shower, the safer course is to keep it out of a shower. Various cement board brands are available – some include integrated waterproofing while others require separate waterproofing applications. Specifically, the Tile Council of North America allows for fiber cement backer board, foam core backer board, and cement backer board, all of which are fine. Unfortunately, they also allow for two backer boards that are somewhat water sensitive gypsum based boards. Because gypsum in showers has cost millions of dollars of property damage, we’ll take a pass on any gypsum based product when so many better alternatives exist.

6. Secure backerboard only with specialized screws recommended by the cement board manufacturer, not standard drywall screws. The heavier weight of cement board and tile demands stronger fasteners than those used for drywall. (But unfortunately, they are sold in big box stores right next to drywall screws).

7. Follow the manufacturer’s guidelines for screw quantity and spacing. At a minimum these should be followed, and a few extras won’t hurt.

8. While scoring and snapping cement board works for some products, many brands cut that way develop uneven, crumbly edges that create gaps between panels. Diamond blade cutting ensures clean, precise edges. For the crumbly types, if possible, cut cement board outdoors with a diamond blade grinder rather than scoring and snapping. Outdoors because of the dust created by dry grinding.

9. The least complicated way to determine shampoo niche locations is to base it on stud placement, which isn’t visible until demolition. That approach requires being flexible beforehand on exactly where the niche will be placed. Access to a good carpenter, though, can enable you to plan to rearrange the framing if you have your heart set on a location that won’t currently fit. Not all tile contractors are comfortable doing that level of carpentry, so you may need another person to handle that.

10. There is more than one way the contractor can hang the cement board. One common approach is to hang it so its bottom edge sits slightly above the tub’s surface, in front of the tub flange (the raised lip on three sides of most porcelain tubs). Achieve this by temporarily placing shims between the tub and cement board during installation. This prevents wicking of water into the cement board. For Jacuzzi-style tubs without flanges, you need to rely on properly applied caulk between tub and tile and keep that joint in good condition, since it’s the ‘last line of defense’ against water leaks.

11. Join cement board panels with seams reinforced with alkaline-resistant cement board tape embedded in thinset mortar. Do not use standard drywall tape, which deteriorates in alkaline environments, like thinset mortar. And, of course, drywall tape is right next to the correct board tape in big box stores, so installers could choose the wrong product by mistake. Rapid setting thinset mortar is acceptable for this application to reduce waiting time. See photo below of cracks developed by doing this step wrong.

13. It’s also possible to waterproof behind the cement board. While it may be effective in keeping water away from the wooden or metal studs, we find this approach less than optimal because the cement board itself is not waterproofed in front. That means it can absorb water and become soaked over time. That can lead to water from the board wicking into nearby drywall just outside the shower. Notice in the first photo below how the lower part of the cement board, exposed during a repair job we did, is darker because it’s absorbed so much water. Notice the second photo of what drywall damage looks like, most likely caused by wicking action.

14. For tile installation, use only properly mixed thinset mortar—never ‘premixed thinset’ or mastic in wet areas, even if some building standards allow them. Contractors sho