Tile installation has several critical stages where the decisions that determine long-term performance happen before the finished surface is visible. The waterproofing must be verified before tile covers it. The layout must be established before adhesive is applied. Mortar coverage must be checked while tiles are still liftable. Knowing what to ask and when is how you confirm the job is being done correctly while there’s still time to correct it.
“The best time for a homeowner to ask questions during a tile job is before each major phase starts — before waterproofing is covered by tile, before adhesive goes down on a full section, before grout is mixed. Those are the moments when a quick conversation confirms the plan and catches anything that needs adjusting. After the tile is set and the mortar has cured, corrections involve demolition.”
— 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
Table of Contents
Before Work Starts
Can you walk me through the substrate and waterproofing plan before any installation begins?
Ask the setter to describe what will happen in sequence — substrate preparation, waterproofing application, layout establishment — before any material is applied. This is your opportunity to confirm that the plan matches what was agreed in the contract, and to ask about anything that’s unclear.
Are all materials on site, and can I verify the products?
Before work begins, ask to see the thinset, grout, and waterproofing product bags or containers. Confirm the product names match what was specified in the quote. A professional tile setter will have no objection to this.
During Substrate and Waterproofing
Can I see the waterproofing before tile covers it?
For shower installations especially, ask to inspect the waterproofing membrane before any tile is installed:
- For KERDI: Is the membrane fully bonded to the substrate with no bubbles or unembedded areas? Are all seams taped with KERDI-BAND and embedded in thinset? Is the drain properly integrated with the KERDI drain flange?
- For liquid membranes: Has the required number of coats been applied? Does the membrane cover the full area including corners, seams, and the floor-to-wall transition?
Take photographs at this stage. These are the only photos you’ll ever have of what’s behind your tile.
Is the shower floor sloped correctly to the drain?
Before tile goes on the shower floor, verify the slope. Place a level on the floor and confirm water will flow toward the drain from all directions. A 1/4″ drop per foot is the standard.
During Tile Setting
Can I see the back of a tile being lifted for coverage verification?
Ask the setter to lift a freshly set tile (before the mortar skins over — typically within 5–10 minutes of setting) and show you the back. The mortar contact should cover at least 80% of the tile back for floors, 95% for wet areas. If coverage is consistently below these thresholds, the trowel notch size or application technique needs adjustment.
Is the layout following the plan?
Walk through the installation periodically and compare what you see to the layout that was established. Are cuts falling where they were planned? Is the pattern consistent? Are grout joints even?
Are tiles being checked for level and plumb as they’re set?
For wall tile especially, ask whether the setter is using a level periodically to confirm tiles are plumb (vertical) and level (horizontal). Tiles that drift over a run require correction before the run is complete.
Is lippage being controlled for large-format tile?
For large-format tile, ask whether a tile leveling system (clips and wedges) is being used. Look at set tiles from a low angle — any visible lippage (one tile edge higher than its neighbor) should be addressed before the mortar cures.
During Grouting
Is the grout being mixed correctly?
Grout must be mixed to the correct consistency — too wet produces a weaker, more porous grout with color variation; too stiff is difficult to force into joints fully. Ask the setter what consistency they’re targeting and how they know when it’s right.
How long will the grout cure before it’s sealed or exposed to water?
Most grout should cure for a minimum of 72 hours before sealing, and before exposure to water in a shower. Ask specifically how long the grout needs before the shower can be used.
Are expansion joints (movement joints) being installed where required?
TCNA (Tile Council of North America) and TTMAC standards require movement (expansion) joints at specific locations:
– At changes in plane (wall-to-floor transition)
– At structural columns and walls
– Where tile abuts dissimilar materials
– In large fields, at regular intervals (typically every 8–12 feet in interior applications)
These joints are filled with a flexible sealant (caulk), not grout. Ask whether movement joints are being incorporated at appropriate locations.
At the End of the Job
Walk the completed work before final payment.
Before making final payment, walk the completed installation with the setter:
- Check all grout joints for consistent width and depth
- Check for any hollow-sounding tiles (tap lightly with a coin — a hollow sound indicates inadequate mortar coverage)
- Check corners and transitions for clean caulk joints where required
- Confirm the shower drains completely with no standing water
- Check all cuts for cleanliness and proper edge treatment
- Confirm all tile is clean — no mortar haze, grout residue, or adhesive on the tile surface
Raise anything that needs to be addressed before the setter leaves.
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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