What is the best grout spacing for bathroom floor tiles in a Vancouver home?

For most bathroom floor tiles in a Metro Vancouver home, a grout joint width of 1/8 inch (3 millimetres) is the standard for rectified (precision-cut) tiles, while 3/16 inch to 1/4 inch (5 to 6 millimetres) is appropriate for non-rectified tiles with slightly irregular edges. The right grout spacing depends on your tile type, size, and format — not just personal preference.

Grout joints serve three important functions beyond aesthetics: they accommodate slight variations in tile size and flatness, they allow for building movement (particularly relevant in Metro Vancouver's Seismic Zone 4), and they provide slip resistance on wet bathroom floors. Eliminating grout joints entirely — sometimes called "seamless" or "butt-joint" installation — is not recommended and violates tile industry standards (TCNA Handbook guidelines).

Rectified porcelain tiles — which have been precision-ground to exact dimensions after firing — can be installed with narrow 1/16-inch to 1/8-inch grout joints. This creates the sleek, minimal-grout look many homeowners want. However, even with rectified tiles, most Metro Vancouver installers recommend 1/8 inch as the practical minimum for floor installations. Anything narrower makes it difficult to fully fill the joint with grout, leaving voids where moisture collects — a real concern in Vancouver's 75 to 85 percent ambient humidity.

Non-rectified (pressed or natural-edge) tiles have slightly irregular edges and dimensions, requiring wider grout joints of 3/16 inch to 1/4 inch to accommodate these variations. Using too narrow a grout joint with non-rectified tiles results in uneven lines and lippage (adjacent tiles sitting at slightly different heights). Most ceramic tiles and some porcelain tiles are non-rectified.

Large-format tiles (24x24 inches and larger) should use 1/8-inch grout joints with rectified edges. The wider the tile, the more visible any grout line irregularity becomes, so precision is critical. Large-format installations also require the substrate to be flat to within 1/8 inch over 10 feet — if the subfloor isn't perfectly prepared, wider grout joints won't hide the resulting lippage.

Mosaic tiles (2x2 inches and smaller), commonly used on shower floors, come pre-spaced on mesh sheets with grout joints typically set at 1/8 inch. These joints are functional — they provide essential slip resistance on wet shower floors and allow the mosaic sheet to follow the shower floor's slope to the drain.

Grout type matters as much as joint width in Vancouver's climate. For bathroom floors, you have two primary options:

Cement-based grout (sanded for joints 1/8 inch and wider, unsanded for joints under 1/8 inch) is the traditional choice at $1 to $3 per square foot installed. It must be sealed after curing — typically 48 to 72 hours — and resealed annually in a bathroom. Unsealed cement grout absorbs water, stains, and harbours mould. In Metro Vancouver's humid environment, neglected cement grout is the number one source of bathroom floor mould complaints.

Epoxy grout is waterproof, stain-proof, and mould-resistant without sealing — making it the superior choice for Metro Vancouver bathrooms despite costing more at $3 to $6 per square foot installed. Epoxy grout is harder to apply and has a shorter working time, so it requires an experienced installer. But it eliminates the annual sealing requirement and provides dramatically better performance in humid conditions. For a 50-square-foot bathroom floor, the price difference between cement and epoxy grout is roughly $100 to $150 — a worthwhile investment.

Colour selection has practical implications beyond aesthetics. Lighter grout (white, ivory, light grey) shows staining and mould more readily than medium-toned grout. In a Metro Vancouver bathroom where humidity is a constant battle, a medium grey or warm taupe grout is more forgiving between cleanings than bright white — unless you're using epoxy grout, which resists staining regardless of colour.

One final detail: always use 100% silicone caulk — not grout — at all change-of-plane transitions (where the floor meets the wall, where the floor meets the tub or shower base, and around any penetrations). These joints need to flex with building movement, and rigid grout will crack. Use a colour-matched silicone for a clean appearance.