Tile installation failures — showers that leak, tiles that hollow out and crack, grout that stains permanently — almost all originate in the preparatory stages that happen before the first tile is set. By the time you can see a problem, the work that caused it is buried under your tile. The warning signs that predict these failures are almost always visible before the contract is signed.
“The red flag that predicts more shower failures than anything else is standard drywall proposed as the substrate. When I see that in a quote or hear it from a homeowner who had work done elsewhere, I know exactly what’s going to happen. The drywall absorbs moisture through the grout joints and around the edges over time, and eventually the tile debonds and the wall behind it is compromised. It’s one of the most common and most preventable tile installation failures.”
— Adaeze Nwosu, certified tile installer and member of the Terrazzo Tile and Marble Association of your country with 17 years of experience in residential and commercial tile installation in the local area
Red Flags Before You Hire
Standard drywall (or greenboard) proposed as substrate in a shower or wet area. This is a fundamental installation error. Standard gypsum drywall — including moisture-resistant greenboard — is not appropriate behind tile in a shower or sustained wet environment. Any proposal involving standard drywall in a shower should prompt an immediate question about the correct substrate, and if the answer doesn’t improve, find a different installer.
No waterproofing membrane specified for a shower. The substrate alone is not waterproofing. Ask specifically what membrane system will go on top of the substrate. An installer who says “the tile and grout keep water out” is not correct and is not current on installation standards. Grout is porous — water moves through it.
No layout plan shown before installation begins. Setting tile without establishing a layout is guessing at the outcome. Any installer who proposes to start setting without showing you where cuts will fall and how the pattern will center is making decisions that will affect the finished appearance without your input.
Unable to specify the thinset being used. A professional tile setter knows exactly what thinset they’re using and why it’s appropriate for the tile and substrate combination. Vague answers about “good tile adhesive” indicate a lack of product knowledge.
Significantly lower price than other quotes without explanation. Tile installation shortcuts are in the substrate, the waterproofing, and the mortar coverage. A dramatically lower price almost always reflects one or more of these being skipped or reduced.
No mention of mortar coverage standards. ANSI A108 requires 80% mortar coverage on floors and 95% in wet areas. A tile setter who has never heard of these standards, or who dismisses them, is not working to professional installation requirements.
Quote provided without a site visit for a shower installation. An accurate tile installation quote requires seeing the space — current substrate condition, floor condition, drain location, niche requirements, ceiling height. A price provided over the phone for a shower installation is a guess.
Red Flags During the Job
Standard drywall going up on shower walls. If you observe standard gypsum drywall being installed on shower walls rather than cement board or foam board, stop the job immediately and ask why the agreed substrate isn’t being used.
No waterproofing membrane applied before tile begins. If the setter moves directly from substrate installation to tile setting without applying any waterproofing membrane, ask what waterproofing is being done and when.
No layout lines established before tile is set. Setting tile without chalk lines or laser reference is guessing at the layout. Ask to see the layout established before any tile goes down.
Mortar coverage not being checked. If you ask to see the back of a lifted tile and the setter seems unfamiliar with coverage verification, or if you see sparse coverage on the backs of lifted tiles, the installation is not meeting standards.
Tile set in a shower without drain integration detail. The connection between the waterproofing membrane and the drain body must be properly sealed. If the drain is just sitting in the mortar without visible integration with the membrane system, ask how the seal is being made.
Related Questions
- Questions to Ask a Tile Setter Before You Hire One
- Questions to Ask a Tile Setter About Waterproofing and Substrate
- What to Do If a Tile Setter Does Bad Work
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