Grout lines fail long before tile does. They are more porous than the tile itself, so dirt, grease, and moisture soak in over time, and the sealer protecting them wears out years before the floor needs replacing.
We clean, reseal, and regrout tile floors across San Diego County, and install waterproof vinyl plank for homeowners who want a grout-free alternative. This guide covers sanded versus unsanded grout, how often to reseal, and when cleaning alone will not fix a failing floor.
Need help with grout that will not come clean? Request a free in-home estimate or call +1 (619) 777-4334.
Sanded vs Unsanded Grout and Why the Cleaning Method Is Different
Grout comes in two basic types, and knowing which one is on your floor changes how you should clean it. Sanded grout has fine sand mixed into the cement for added compressive strength, and it is used in joints 1/8 inch (about 3 mm) or wider, the standard spacing on most 12x24 inch and larger floor tile. Unsanded grout is smoother and finer, used in joints narrower than 1/8 inch, and is common on wall tile, glass or ceramic mosaics, and polished natural stone, where a coarse sanded mix could scratch the finish.
The Tile Council of North America (TCNA) sets the joint width standards most installers follow, and you can review them directly at the Tile Council of North America. The practical difference for cleaning comes down to texture. Sanded grout's rougher surface traps dirt between the sand grains, so it needs a stiffer nylon-bristle grout brush and a slightly longer dwell time for the cleaner to break up grime. Unsanded grout is smoother and sheds debris more easily, but it is also softer, so a soft-bristle brush works better and protects narrow joints from being scoured out over repeated cleanings.
Both types are still porous cement at the core, which is why both need a sealer and both stain the same way from wine, coffee, grease, and soap scum. The grout type does not change what cleaner to avoid. Skip chlorine bleach on colored grout, since it lightens color unevenly, and skip vinegar or other acidic cleaners on both grout types and on natural stone tile, since acid dissolves the cement binder in grout and etches stone over time.
Joint width also affects how much maintenance you sign up for. Wide sanded joints of 3/8 inch or more, common on Spanish paver-style tile, expose more total grout surface per square foot of floor, which means more area to clean and reseal over the life of the floor. If you are choosing tile for a remodel and want less grout upkeep down the road, rectified tile edges allow for tighter joint spacing, often 1/16 to 1/8 inch, without changing the overall look much.
How to Clean Grout Lines Step by Step
Routine grout cleaning takes 20 to 40 minutes for an average kitchen floor and does not require harsh chemicals. Here is the process we recommend:
- Sweep or vacuum first. Grit left on the floor acts like sandpaper once you start scrubbing and can dull the grout surface and any remaining sealer.
- Mix a cleaner. For routine dirt, use a pH-neutral tile cleaner or a paste of 3 parts baking soda to 1 part water. For tougher grime or mildew, use an oxygen-based (hydrogen peroxide) cleaner instead of chlorine bleach.
- Apply and let it dwell. Spread the paste or cleaner directly onto the grout lines and let it sit for 10 to 15 minutes so it can loosen embedded dirt before you scrub.
- Scrub along the joint, not across the tile face. Use a nylon grout brush, stiffer bristles for sanded grout, softer for unsanded, and work in short strokes following the line of the grout.
- Rinse with clean water and dry. Standing water left sitting in grout lines invites mildew and shortens sealer life, so wipe or dry-mop the floor after rinsing rather than letting it air dry.
How often you need the deep-clean version depends on the room. Kitchens and entryways collect grease and tracked-in dirt fast enough to need a real grout scrub every 4 to 6 weeks. Bathrooms need it every 6 to 8 weeks because of soap scum and body oil buildup. Low-traffic rooms like guest bathrooms or formal dining rooms can go 3 to 4 months between deep cleans if you keep up with weekly sweeping and damp mopping in between.
How Often Should You Reseal Grout Lines?
Standard cement-based grout is porous, and the penetrating sealer applied over it wears down with foot traffic, cleaning chemicals, and water exposure. On floors in kitchens and entryways, where foot traffic and grit are heaviest, reseal every 12 to 18 months. On bathroom walls and shower surrounds, where traffic is lighter but water exposure is constant, reseal every 2 to 3 years. Low-traffic areas like guest bathrooms or basement floors can often go 3 to 5 years between resealing.
Coastal San Diego homes tend to wear through sealer faster than inland ones. In neighborhoods like La Jolla and Coronado, salt air and higher year-round humidity shorten sealer life by roughly 20 to 30 percent compared to inland areas, which usually means resealing closer to the 12-month mark instead of 18.
The simplest way to check if grout needs resealing is a water test. Pour about a tablespoon of water directly onto a grout line. If the water beads up and sits on the surface for 5 to 10 minutes without soaking in, the sealer is still doing its job. If the grout darkens and absorbs the water within about 60 seconds, the sealer has worn through and it is time to reseal. Epoxy grout is the one exception. It is non-porous by nature and does not need a separate sealer at all, though it costs more upfront and is harder to install than standard cement grout.
| Sealer Type | How It Works | Reapplication | Best For |
|---|---|---|---|
| Penetrating (impregnating) | Soaks into the porous grout and repels water and stains from within | 12 - 36 months depending on traffic | Most residential floors and walls |
| Membrane-forming (topical) | Forms a thin coating on top of the grout surface | 6 - 12 months, wears faster underfoot | Low-traffic accent areas, backsplashes |
We use penetrating sealer on nearly every residential job, since it holds up better under foot traffic and does not peel or wear unevenly the way a topical coating can on a floor.
How to Reseal Grout Lines the Right Way
Resealing is a straightforward DIY job as long as the grout is otherwise in good condition, meaning no cracks, no missing sections, and no separation from the tile. Here is the process:
- Clean and dry completely. Deep clean the grout first, then let it air dry fully, 24 hours in a well-ventilated room or up to 48 hours in a humid bathroom. Sealer applied over damp grout traps moisture underneath and fails early.
- Apply a thin, even coat. Use a small chip brush, foam applicator, or a dedicated sealer pen (better for precision on narrow unsanded joints) and run it directly along the grout line.
- Wipe excess within 3 to 5 minutes. Sealer left to dry on the tile face leaves a visible haze that is a hassle to remove once cured, so wipe the tile surface with a clean microfiber cloth before it sets.
- Apply a second coat for high-traffic floors. Kitchens and entryways benefit from two coats for added protection. A single coat is usually enough for bathroom walls or low-traffic rooms.
- Let it cure before use. Keep foot traffic off the floor for 24 hours, and avoid water contact, including showering over resealed shower grout, for 48 to 72 hours.
Supplies for a DIY reseal run $25 to $50 for a quart of penetrating sealer plus an applicator, and that quantity typically covers 200 to 300 square feet of grout lines, enough for an average kitchen or two bathrooms.
DIY Grout Cleaning vs Professional Regrouting
Cleaning and resealing are DIY-friendly jobs. Regrouting, meaning removing and replacing the grout itself, is a different project, and it is usually worth hiring out once grout has actually failed rather than just gotten dirty. Regrouting involves grinding out the old grout with an oscillating multi-tool or a manual grout saw down to bare tile edges, vacuuming out the dust and debris, then mixing and packing new grout into clean joints before it can bond properly. Skipping the full grind-out and packing new grout over old is a common DIY shortcut that fails within months, since new grout will not bond to old grout residue.
| Task | Typical Cost | Time | Best For |
|---|---|---|---|
| DIY cleaning | $10 - $25 in supplies | 30 - 60 minutes per room | Routine maintenance, light staining |
| DIY resealing | $25 - $50 in supplies | 2 - 4 hours per room, plus cure time | Grout in good condition, due for routine sealer |
| Professional regrout, bathroom (~50 sqft) | $200 - $450 | About 1 day | Cracked, crumbling, or missing grout |
| Professional regrout, kitchen floor (~150 sqft) | $500 - $1,050 | 1 to 2 days | Grout failure across a larger floor area |
| Full tile and grout replacement | $8 - $18 per sqft installed | 3 - 5 days | Grout failure tied to a subfloor or waterproofing issue |
If grout keeps failing in the same spot within months of a regrout, the problem usually is not the grout itself, it is what is underneath it. That pattern often points to subfloor movement, a cracked slab, or a waterproofing failure in a wet area, and no amount of regrouting fixes it until the underlying issue is addressed.
Signs Your Grout Needs Replacing, Not Just Cleaning
Cleaning and resealing fix dirty or fading grout. They do not fix grout that has already failed structurally. Watch for these signs:
- Grout crumbles or turns to powder when you scrape it with a fingernail or the edge of a flathead screwdriver.
- A visible gap between the grout and the tile edge, more than a hairline, which usually means the grout has shrunk, cracked, or separated from movement underneath.
- Dark stains or mildew that come back within a week of cleaning and resealing, which usually means moisture is getting in from underneath rather than sitting on the surface.
- Missing grout chunks larger than about a quarter inch in more than one or two spots.
- A hollow sound when you tap the tile near the grout line, which can mean the tile has lost its bond to the substrate.
- Grout color that stays blotchy or patchy even after two cleaning and resealing attempts, which usually means the cement itself has degraded and sealer can no longer penetrate evenly.
Any one of the first two signs alone might just need a regrout. Multiple signs together, especially hollow-sounding tile or recurring moisture, usually mean the issue goes deeper than the grout and the tile itself needs to come up for a proper repair. If you are not sure which situation you are looking at, our free in-home estimate includes a look at the tile and subfloor, not just the grout lines.
Frequently Asked Questions
How often should you reseal grout lines?
Reseal grout on floors every 12 to 18 months and on shower or bathroom walls every 2 to 3 years. Homes near the coast in areas like La Jolla or Coronado often need resealing closer to the 12 month mark since salt air and higher humidity break down sealer faster.
What is the difference between sanded and unsanded grout?
Sanded grout contains fine sand and is used in joints 1/8 inch or wider, common on floor tile. Unsanded grout is smoother, used in joints under 1/8 inch, and is common on walls, mosaics, and polished natural stone where sand could scratch the surface.
Can you clean grout without damaging the sealer?
Yes, if you stick with a pH-neutral cleaner or a baking soda paste and a nylon grout brush. Avoid chlorine bleach, which lightens colored grout unevenly, and avoid vinegar or other acidic cleaners, which break down cement grout and etch natural stone over time.
How do you know if grout needs to be resealed?
Pour a tablespoon of water onto a grout line. If it beads up and sits on the surface for 5 to 10 minutes, the sealer is still working. If the grout darkens and absorbs the water within about 60 seconds, it is time to reseal.
Should I clean and reseal grout myself or hire a professional?
DIY cleaning and resealing works well for grout that is intact but stained or due for routine sealer. Call a professional when grout is cracked, crumbling, missing in chunks larger than a quarter inch, or separating from the tile edge, since those signs usually mean a regrout or tile repair is needed instead.
How much does professional regrouting cost?
Professional regrouting typically runs $3 to $7 per square foot of tile area, or about $200 to $450 for an average 50 square foot bathroom and $500 to $1,050 for a 150 square foot kitchen floor, depending on tile size and grout condition.
Does epoxy grout need to be sealed?
No. Epoxy grout is non-porous and resists stains and water without a separate sealer coat, which is why it holds up well in kitchens and bathrooms. Standard cement-based grout is porous and does need a penetrating sealer on a regular schedule.
Can grout be repaired without replacing the whole floor?
Yes, in most cases. A professional can grind out and replace failing grout in a section or an entire room without removing the tile itself, as long as the tile is still well-bonded and the subfloor underneath has not been damaged by water.