How do I clean and maintain grout in a Vancouver bathroom to prevent mould long term?

The key to preventing mould in bathroom grout in Metro Vancouver is a three-part approach: proper sealing, regular cleaning with the right products, and adequate ventilation to control the persistent humidity that makes Vancouver bathrooms especially prone to mould growth. Vancouver's year-round humidity averaging 75–85% means grout maintenance here requires more diligence than in drier Canadian climates — mould can establish in unsealed grout within weeks of a new installation if ventilation is poor.

Sealing is your first line of defence. Standard cement-based grout is porous — it absorbs water, soap residue, and organic matter that feed mould colonies. After new grout has fully cured (typically 48–72 hours), apply a penetrating grout sealer that soaks into the grout and creates a moisture barrier from within. Quality penetrating sealers like Aqua Mix Sealer's Choice Gold or TileLab SurfaceGard cost $15–$30 per bottle and cover 200–500 square feet. Apply the sealer with a small foam brush, wiping excess off the tile face, and allow it to cure per the manufacturer's instructions. Reseal your grout every 12 months in a Vancouver bathroom — twice a year for shower grout that sees daily use. You can test whether your sealer is still working by dripping water on the grout line: if the water beads up, the sealer is intact; if it soaks in and darkens the grout, it is time to reseal.

Alternatively, if you are installing new tile or regrouting, consider epoxy grout instead of cement grout. Epoxy grout (such as Laticrete SpectraLOCK or Mapei Kerapoxy) is waterproof, stain-proof, and naturally mould-resistant without sealing. It costs more ($50–$80 per unit versus $10–$20 for cement grout) and is harder to apply — most homeowners prefer to leave epoxy grouting to a professional tile installer, which adds $2–$5 per square foot to installation costs. But in Vancouver's humid climate, the long-term maintenance savings and mould resistance make epoxy grout an excellent investment, especially in showers.

For routine weekly cleaning, use a pH-neutral bathroom cleaner or a simple mixture of equal parts white vinegar and water sprayed onto grout lines. Let it sit for 5–10 minutes, then scrub with a stiff nylon brush (not metal, which can damage grout). Rinse thoroughly and dry the surface. For tougher mould stains that have already developed, use a hydrogen peroxide-based cleaner (3% hydrogen peroxide applied directly to the grout, left for 10–15 minutes, then scrubbed and rinsed). Hydrogen peroxide kills mould without the harsh fumes of chlorine bleach and does not degrade grout sealers as aggressively.

Avoid chlorine bleach for regular grout cleaning. While bleach kills surface mould effectively, it also breaks down penetrating grout sealers, degrades cement grout over time, and produces toxic fumes in the enclosed, poorly ventilated space of a shower. If you must use bleach for a severe mould outbreak, reseal the grout after the treatment.

Ventilation is the most critical long-term mould prevention measure for any Vancouver bathroom. Your exhaust fan should be rated at minimum 50 CFM for a small bathroom (under 50 square feet) or 80–110 CFM for a larger bathroom. It must vent to the exterior — never into an attic, soffit, or wall cavity, where the moisture simply moves the mould problem to a different location. Run the fan during every shower and for at least 20–30 minutes after — a timer switch ($30–$80 at any Metro Vancouver electrical supplier, $150–$300 installed by an electrician) makes this automatic. Even better, install a humidity-sensing fan ($150–$400 for the fan unit) that turns on automatically when humidity rises and shuts off when the air has dried. In Vancouver, where outdoor air is already humid, the fan needs to run longer than in drier climates to achieve the same moisture reduction.

Squeegee your shower walls and glass after every use. This takes 60 seconds and removes the standing water that mould needs to grow. It is the single most effective daily habit for preventing grout mould in a Vancouver bathroom. Keep a squeegee hanging in the shower where it is easy to grab.

If your grout is already severely moulded, stained, or crumbling, professional regrouting may be necessary. A tile professional can remove the old grout with an oscillating tool, clean the joints, and apply new grout (ideally epoxy for wet areas) without disturbing the existing tiles. Professional regrouting in Metro Vancouver typically costs $8–$15 per square foot, or $800–$2,000 for a standard shower. This is far less expensive than tearing out and retiling, and it gives your existing tile installation a fresh start with proper mould-resistant grout.