How to Clean Grout Without Damaging It

Most residential grout is cement-based and porous, although epoxy and other specialty grouts behave differently. Before choosing a cleaner, identify the grout and the tile around it. A product that is safe on porcelain may etch marble, discolor stone, or damage a sealer.

Start by vacuuming or sweeping away loose grit. Then use warm water and a stiff nylon grout brush. Work a small section at a time and wipe up the dirty water before it dries back into the joint. Skip wire brushes because they can cut into grout and scratch the tile beside it.

If water isn't enough, use a pH-neutral tile-and-grout cleaner and follow the label's dilution and dwell time. Give the product time to loosen soap film and body oils, then agitate with the nylon brush. Rinse more than once because cleaner left in a porous joint can attract new soil.

For stubborn organic staining, an oxygen bleach product labeled for your type of grout may help. Test colored grout first, ventilate the room, wear the protection listed on the label, and keep the product off surfaces the label excludes.

Don't make vinegar or another acid the routine next step. Cement-based grout is alkaline, and acid removes a small amount of its surface. Repeated use can weaken the joint and damage some sealers. Acid can also etch marble, limestone, travertine, and other natural stone even when the grout itself looks fine.

Chlorine bleach isn't a general-purpose grout cleaner either. It may lighten some discoloration, but it can affect colored grout, sealers, metals, and nearby stone. Never mix bleach with vinegar, ammonia, or another cleaner. If a product containing bleach is appropriate for a specific surface, use it only as labeled and rinse completely.

Steam can loosen soil without leaving chemical residue, but heat and pressure may expose weak grout or shorten the life of some sealers. Check the tile, grout, and sealer instructions before using it, keep the nozzle moving, and stop if the joint begins to pit or crumble.

While you clean, inspect the corners where two tiled surfaces meet. Those changes of plane usually need a flexible sealant rather than a rigid grout joint. Cracked or missing sealant is a repair issue. Recurring dark growth, loose tile, soft wall material, or a persistent musty smell can point to trapped moisture that cleaning alone won't solve.

Let the grout dry fully before deciding whether it needs sealer. Some cement-based grout benefits from a penetrating sealer, while epoxy and certain newer grouts may not need one. Follow the grout manufacturer's instructions for drying time, product choice, and reapplication instead of sealing by a fixed calendar.

This comes up most on deep cleaning jobs. All cleaning tips.