Is a Hollow-Sounding Floor Covered Under the Tile Manufacturer's Warranty?

A tile manufacturer's warranty is a promise about the object, not the installation. It covers things that happen at the factory: glaze crazing, dimensional warping out of spec, uneven color lots, structural weakness in the body of the tile. A hollow sound coming from under a set tile is not evidence of any of that — it's evidence of a gap between the tile and the substrate, which is a mortar application problem, and mortar application is the installer's responsibility, not the manufacturer's.

When a warranty claim gets filed over hollow tile, the inspector's first move is to pull a sample tile and check mortar coverage on the back, because that's the documented standard the industry uses to separate a product failure from a workmanship failure. Interior dry floors need a minimum of 80% mortar coverage on the tile back and substrate combined; wet areas, exterior installs, and large-format tile need 95%. If coverage comes in under that line, the claim gets closed as an installation issue almost automatically, no matter how the tile itself performed.

Large-format tile makes this worse in practice. Anything with an edge over 15 inches falls under stricter back-buttering rules precisely because bigger tiles bridge low spots in the substrate more easily, leaving voids that sound hollow the day the mortar cures — sometimes before the grout even goes in. If your floor uses plank-format or large-format porcelain, the odds that a hollow spot traces back to coverage rather than a bad batch of tile go up substantially.

There's one real exception: full-system warranties. Some manufacturers — and more commonly the mortar and membrane brands, since they publish system warranties more aggressively than tile brands do — will cover both material and labor if every component (tile, mortar, membrane, grout) comes from their own product line and the job was installed and registered by one of their certified installers. That's a materially different document from the standard tile-only warranty, and it's the only scenario where a hollow-sounding floor has a real shot at being covered as-is.

Outside of that, the workmanship itself is usually covered by a separate agreement — the installer's own labor warranty, not the tile manufacturer's. Trade practice generally puts that at around 1 year, covering callbacks for things like hollow spots, lippage, and grout failure that show up shortly after the job. If that window has closed and there's no certified full-system install on file, there's no warranty path left to pursue — the repair becomes an out-of-pocket cost regardless of who's at fault.

Registration matters too. A number of system warranties require the installer to submit a project registration within a set window of completion; skip that step and the warranty coverage never activates in the first place, even if every material on the job qualifies.

The most expensive mistake is delay. Homeowners hear a hollow tap, assume it's cosmetic, and wait — meanwhile the unsupported tile flexes under foot traffic, the bond breaks down further, and adjacent tiles start drumming too. What started as a two- or three-tile repair turns into a section of floor that needs to come up entirely, and by the time someone finally calls the manufacturer, there's no warranty angle left to use and a much bigger tear-out bill to cover.

The second mistake is filing a claim without documentation and getting denied, then paying for the redo without ever pricing it properly. If a claim is going to be denied on coverage grounds, it's worth knowing what the fix actually costs before agreeing to anything. Run the affected area through the /floor-tile-calculator to get a material estimate for the section coming up, and use the /tile-estimator if you're buying replacement tile that has to match an existing run and account for box-level waste.

The third mistake is re-tiling with the same mortar and technique that caused the void the first time. A denied warranty claim is still useful information — it tells you the coverage standard wasn't met, which means the fix needs to actually hit 80% (or 95% for large-format) this time, not just look flat after grouting.

Photograph the hollow area before anything gets touched, and if a tile is going to be pulled anyway, photograph the mortar pattern on the back — full coverage looks like a solid skim; low coverage looks like isolated ridges with bare substrate between them. That photo is the single piece of evidence a warranty desk or a manufacturer's field rep will ask for first.

Pull the original invoice for the mortar and tile, and check whether either product was part of a registered system install. If it was, the claim goes to the system brand, not the tile brand, and the registration paperwork is what makes or breaks it. If it wasn't, treat the labor warranty — if the installer offered one — as the only coverage that exists, and act inside that window rather than after it closes.