Should I use caulk or grout in the corners and edges of my Ottawa bathroom tile?

Caulk — every time. Inside corners, where tile meets the bathtub or shower pan, where tile meets the ceiling, and where tile meets any different material or surface should always be filled with a flexible silicone or polyurethane caulk rather than grout. This is not just a best practice — it is an industry standard backed by the Tile Council of North America (TCNA) and is especially critical in Ottawa homes.

The reason is movement. Every building shifts, settles, and expands and contracts with temperature and humidity changes. In Ottawa, this movement is amplified by our extreme seasonal swings — from bone-dry winter air at 20 percent humidity indoors to muggy summer conditions exceeding 80 percent outside. Wood-framed homes in particular expand and contract measurably between seasons. Grout is rigid and brittle. When two surfaces move even slightly in different directions — which they always do at corners, transitions, and change-of-plane joints — rigid grout cracks. Caulk is flexible and accommodates that movement without cracking.

The most common place homeowners notice the problem is where the bathtub meets the tile surround. The tub flexes slightly under the weight of water and a person, while the wall tile stays put. Grout in that joint will crack within months. Along the vertical inside corners of a shower, the two walls expand and contract independently, and grouted corners will eventually crack and allow water behind the tile — a serious waterproofing concern.

Use 100 percent silicone caulk for wet areas like showers and tub surrounds. Silicone is waterproof, flexible, and mould-resistant. Avoid latex or acrylic caulk in showers — it is not truly waterproof and will deteriorate faster. Match the caulk colour to your grout colour for a seamless look; most major caulk manufacturers offer colour-matched options in the same shades as popular grout colours.

One tip that makes a real difference: remove old caulk completely before recaulking. Scrape it out with a utility knife or oscillating tool, clean the joint with rubbing alcohol to remove any residue, let it dry fully, then apply a smooth, continuous bead of silicone. Applying new caulk over old caulk is a shortcut that never lasts.

This is a DIY-friendly task that most homeowners can handle with a caulk gun, painter's tape for clean lines, and a bit of patience. Expect to recaulk shower and tub joints every three to five years as part of normal bathroom maintenance in Ottawa's climate.

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Looking for experienced contractors? The Ottawa Construction Network connects Ottawa homeowners with qualified professionals:

• Montgomery Construction
• JC Carpentry
• Callandgone
• MAK Construction and Development Inc
• JMY Renovations