The Easiest Way to Transform a Tired Bathroom
Grout is porous, it sits in horizontal joints that collect water and soap scum, and it lives in the most humid room in the house. In a GTA home that's more than 10 years old, chances are the grout in at least one bathroom is discoloured, cracked, or both. The tiles themselves might be in perfect condition — but dark grey grout lines that were originally white can make an entire bathroom look dated and dirty regardless of how much you scrub.
The good news: you don't need to rip out the tile. Depending on how bad the damage is, you can restore grout with one of three approaches: a grout pen (cosmetic fix, 30 minutes), grout renew coating (more durable, a few hours), or full regrouting (the real fix, a weekend). This guide walks you through all three so you can pick the right one for your situation.
⏰ Time Estimate
Grout pen: 30–60 minutes. Grout renew: 2–4 hours. Full regrout of a standard bathroom floor: 4–6 hours across two days.
Diagnose Your Grout First
Run through these questions before buying anything:
- Is it just stained? Try scrubbing with an old toothbrush and a paste of baking soda and white vinegar first. Grout that responds to deep cleaning may only need a sealer refresh, not a full replacement.
- Is it cracked or crumbling? Cosmetic fixes won't hold. You need to regrout those sections at minimum — cracked grout lets water infiltrate behind the tile and causes much bigger problems (including structural damage to GTA homes with older tile-over-drywall showers).
- Is it just discoloured and dull? A grout pen or renew coating will work well here.
- Is there mould throughout? Chlorine bleach in a spray bottle, left for 10 minutes and scrubbed, kills surface mould. If the mould keeps coming back in the same spots, you have a moisture infiltration problem behind the wall — a different issue altogether.
Method 1: Grout Pen (Cosmetic Fix)
A grout pen is essentially a paint marker filled with a water-resistant, tile-safe pigment. It's the fastest way to make stained grout look white again and is ideal for floors or walls where the grout is structurally sound but just discoloured.
Clean the Grout Thoroughly
The pen won't bond over soap scum or mildew. Scrub all grout lines with a stiff brush and a dedicated grout cleaner or a baking soda + vinegar paste. Rinse thoroughly and let the surface dry for at least 2 hours — the grout needs to be bone dry for the pigment to absorb properly.
Apply the Grout Pen
Prime the pen by pressing the tip on a piece of cardboard until the pigment flows. Drag the tip slowly along each grout line in a single steady pass. Work in small sections. The pigment dries quickly — 15–20 minutes — so wipe any accidental coverage on tile faces immediately with a damp cloth. Let fully cure for 24 hours before exposing to water.
Seal Over Top
Once fully cured, apply a penetrating grout sealer over the pen application to extend the life of the finish. The pen alone will wear in high-traffic areas like shower floors within 6–12 months — sealing it can extend that to 2+ years. Reapplication is quick when needed.
💡 GTA Tip
Polyblend Grout Renew and Mapei Grout Refresh pens are both available at Home Depot locations throughout the GTA for $8–$15. Match your existing grout colour — the pen colour chart at the store is reasonably accurate, but when in doubt, go one shade lighter since grout always looks darker when wet.
Method 2: Grout Renew Coating (Durable Refresh)
A grout renew product (like Polyblend Grout Renew or Aqua Mix Grout Colorant) is applied with a small brush and penetrates into the existing grout, restoring colour and adding a sealing layer. It's more durable than a pen and covers larger areas faster. It works best on floor tile where grout lines are wide enough for a brush.
Deep Clean and Degrease
Use a dedicated tile and grout cleaner, not just water. For bathroom floors, a diluted oxygen bleach solution (OxiClean or similar) applied for 10 minutes and scrubbed in is highly effective at lifting embedded soap scum and mildew staining. Rinse completely and allow 24 hours to dry. Any moisture in the grout will prevent proper adhesion of the colorant.
Tape the Tile (Optional but Recommended)
For large floor areas with wide grout joints, applying painter's tape along the tile edges is tedious but produces a much cleaner result. For wall tile with narrow joints, you can free-hand it and clean up with a damp sponge as you go.
Apply the Colorant
Using a small artist's brush or the applicator provided, work the colorant into each grout line in steady strokes. Don't rush — even coverage is what makes this look good. Apply a second coat if needed after the first has dried (30–45 minutes). Remove tape and wipe tile faces with a damp cloth to clean up any bleeds.
Cure and Seal
Keep the treated surface dry for 24 hours minimum. The colorant cures as it dries and does not require a separate sealer — the product is self-sealing. However, a penetrating sealer applied after a week can add extra protection in shower areas.
Method 3: Full Regrouting (The Permanent Fix)
If the grout is cracked, crumbling, missing in places, or badly moulded, cosmetic fixes are a waste of time. The only real solution is removing the old grout and applying fresh. This sounds intimidating but it's a straightforward job — just time-consuming.
Remove the Old Grout
A rotary grout removal tool (available with an oscillating multi-tool attachment) makes this dramatically faster than hand tools. Work it along each grout line to a depth of about 2/3 the depth of the existing grout — you don't need to go all the way to the substrate, just deep enough to get a clean base for new grout. Wear a dust mask and eye protection — old grout generates a lot of fine dust. Vacuum and wipe the joints clean when done.
Check for Damaged Tiles
With the grout removed, you'll be able to press on each tile and feel if any are loose or hollow underneath. A loose tile means the thinset behind it has failed — you'll need to remove it, scrape the old adhesive, and reset it with fresh thinset before regrouting. A loose tile that gets grouted in place will crack within months.
Apply Fresh Grout
Mix unsanded grout (for joints under 3mm) or sanded grout (for joints 3mm and above) to a smooth, lump-free peanut-butter consistency. Work in sections of 4–6 sq ft. Use your grout float at a 45° angle to press grout firmly into all joints, working diagonally across the tile faces. Once the section is packed, wipe the excess with a barely-damp sponge in circular passes, rinsing the sponge constantly. Let the grout firm up (20–30 minutes), then buff off the haze with a dry cloth.
Caulk the Corners and Transitions
Inside corners — where the floor meets the wall, or where a tub deck meets a wall — must be caulked, not grouted. These are movement joints. Apply a bead of colour-matched silicone caulk (not acrylic) in all inside corners and smooth it with a wet finger or caulk tool in one clean pass. Let cure 24–48 hours before exposing to water.
Seal the New Grout
After the grout has cured for 72 hours, apply a penetrating grout sealer to all joints. This is the step most people skip and most people regret — unsealed grout in a GTA bathroom will be stained again within a year. Apply the sealer with the bottle applicator, let it soak in for 5 minutes, and wipe off any excess from the tile faces. Reapply every 2–3 years.
⚠️ Shower Walls — Extra Note
If you're regrouting a shower with tile installed over standard drywall (common in GTA homes built before 2000), be aware that water infiltration through cracked grout over the years may have damaged the drywall behind the tile. If tiles feel loose or the wall flexes, you may be looking at a more involved project — removing tile and replacing the substrate with cement board before retiling. Worth knowing before you start.
Approximate Cost by Method (CAD)
| Method | Materials Cost | Best For |
|---|---|---|
| Grout pen | $8–$20 | Lightly stained, structurally sound grout |
| Grout renew coating | $20–$50 | Heavily stained, otherwise solid grout |
| Full regrout (standard bathroom floor) | $60–$130 | Cracked, crumbling, or missing grout |
| Tile contractor quote (GTA regrout) | $300–$700+ | — |
Final Thoughts
Grout refresh projects have one of the best return-on-effort ratios of any home improvement task. A bathroom with clean, bright grout looks renovated even if nothing else has changed. And unlike a lot of renovation work, the stakes are low — the worst outcome is you go back and do it again, which takes all of 30 more minutes with a pen.
For best long-term results: regrout once properly, seal it, and touch it up with a pen every couple of years as needed. Your bathroom will stay looking sharp without ever needing a professional.