Whether grout needs sealing at all depends entirely on what type it is. Cementitious grout is porous by nature, so it absorbs water, oil and grime unless it’s sealed — leading to staining and, over time, mould. Epoxy grout is a different material entirely and is effectively self-sealing, so it doesn’t need this step. If you’re not sure which type is in your tiling, that’s the first thing to check before deciding whether to seal at all.
Why cementitious grout needs a sealer
Cementitious grout is essentially a porous, cement-based material, and that porosity is exactly what lets stains, oil and moisture soak in over time. A penetrating sealer works by sending sealing molecules down into those pores rather than sitting on top as a film, protecting the grout against staining and water damage while still allowing it to breathe. Stain Proof’s Waterbased Penetrating Sealer works this way, and it’s a genuine step up from leaving cementitious grout unsealed in any wet or high-use area.
When to seal, and how often to reseal
New grout needs to fully cure before sealing — applying sealer too early traps moisture underneath instead of protecting the surface, so follow the grout manufacturer’s cure time rather than guessing. From there, resealing frequency depends on how much wear the area gets: a kitchen splashback or bathroom floor will need resealing more often than a lightly used feature wall. A simple test is to drop a small amount of water onto the grout — if it soaks straight in instead of beading on the surface, it’s time to reseal.
Applying grout sealer properly
A grout sealer roller applicator is worth using over a brush or cloth — it applies the sealer directly and evenly along the grout line without spreading excess sealer across the tile surface itself, which matters because sealer left sitting on a glazed tile can leave a visible residue or haze once it dries. Work in manageable sections, and wipe away any sealer that does land on the tile face before it dries.
Cleaning grout before you seal it
Sealer locks in whatever is already in the grout when you apply it, so cleaning thoroughly first matters more than the sealer choice itself. Davco Tile and Grout Cleaner and the DTA Boss Grout Clean Up System are both built for this step. Let the grout dry fully before sealing — sealing over damp grout is one of the most common reasons a sealing job doesn’t hold up.
Browse the full grout and stone sealer range at Multifors.