Grout selection is one of the renovation decisions that looks minor and isn’t. The wrong grout in the wrong application causes staining, cracking, failure, and expensive repairs. Here’s how to get it right.
The Three Grout Categories
Unsanded (non-sanded) grout: For joints up to 3mm (1/8"). The lack of sand aggregate prevents scratching of polished tile surfaces during installation. Use for: polished marble, glass tile, porcelain tile with tight grout lines.
Sanded grout: For joints from 3mm to 12mm. Sand aggregate increases dimensional stability, reduces shrinkage, and provides better joint performance in wider gaps. Use for: most floor tile installations, wider joint patterns, rough tile.
Epoxy grout: Two-component system (resin + hardener) that cures chemically rather than through water evaporation. Virtually impervious to staining, chemicals, and water. Significantly more difficult to install (short working time, requires immediate cleanup). Cost: 4–6x standard grout. Use for: commercial applications, kitchen counters, swimming pools, grout lines subject to heavy cleaning chemicals.
The Colour Decision
Grout colour affects the entire appearance of a tile installation. Two schools:
Match the tile: Grout that closely matches tile colour creates a unified surface that emphasizes the tile’s pattern and format. Popular with large-format tiles where the joint is minimal.
Contrast the tile: Dark grout on white tile (or vice versa) emphasizes the pattern of individual tiles. Creates a graphic quality.
The practical consideration: Light grout in high-traffic floors stains. Kitchen countertop grout in white or cream will be grey within two years regardless of sealing. Use medium grey or darker grout where maintenance will be an issue.
Grout Sealing in Ontario
Porous grout (cement-based, sanded or unsanded) must be sealed in wet areas and high-traffic floor areas. Seal after installation (24–72 hours after grouting, once fully cured). Re-seal every 1–3 years depending on traffic and cleaning products used.
What sealer doesn’t do: Sealer slows staining — it doesn’t prevent it. Sealed grout still requires cleaning. Epoxy grout doesn’t require sealing.