How to Seal Grout and Keep Grime Out
Once your grout is fresh and intact, here’s your DIY to seal the deal
- Toothbrush
- Sponge/cloth
- Razor blade (optional)
- Grout sealer
- Dish soap
- Grout cleaner (optional)
- Lemon juice (optional)
- Cream of tartar (optional)
Mold and grime can quickly sneak up and taint the look of your grout, causing even the most beautiful tiles to lose their luster. You can fight back by learning how to seal grout with a little determination and grout sealer—plus a few other supplies you likely already have on hand. Sealing your grout will create a barrier against moisture, making it easier to clean and inhibiting the growth of those ugly spores, so this is a process you don’t want to skip.
Prepping to Apply Grout Sealer
You can often clean and repair grout to get it good-as-new, but it might be necessary to replace it first, especially if the damage is extensive.
Whether or not you can tackle this task on your own depends on where your grout is. While you can attempt to regrout your tile floor yourself, it’s an expert-level task, and you’ll typically be better off hiring a local handyperson to help you. On the other hand, DIY shower regrouting is a much simpler task that you may be able to take on if you’re looking to save money.
How to Seal Grout
Once you complete all that important prep work, you can learn how to seal your grout to keep it looking pristine.
Clean and Repair Your Tile Grout
Photo: Tanya Rozhnovskaya / Adobe StockBefore you can start the actual tile grout sealing process, you’ll need to make sure the grout is clean and intact. You can repair loose grout by removing it and applying a fresh layer of new grout.
If your grout is still in good shape but looking a little dull and dingy, be sure to clean your grout first so you’re starting with a fresh slate. You can use an old toothbrush with commercial grout cleaner, or you can sub this out for dish soap, baking soda with or without vinegar, lemon juice with cream of tartar, or even shaving cream. It’s always best to spot-test any cleaner first, though.
To remove excessive amounts of grime, carefully use a razor blade to lift any gunk out.
Choose the Correct Grout Sealer
Picking the right grout sealer can be just as important as picking the right grout itself. It has the power to make your grout shine and your tiles pop or to muddy the whole picture. Depending on whether you have stone, marble, or ceramic tile, you’ll find a variety of different sealers that you can use for each.
Along with the material, you’ll need to take the level of moisture your tile will be exposed to into account. Based on that, there are two types of sealers: Penetrating and membrane-forming grout sealers. Penetrating sealers are designed for maximum water protection, soaking in and sealing the pores in the grout. It is the more durable of the two, protecting from water, mildew, stains, and more. Penetrating sealers are best used in areas exposed to a lot of water, like showers or bathrooms.
Membrane-forming, or non-penetrative, grout sealers are designed to be more aesthetically pleasing, only covering the surface of the grout and giving it a shiny coat. However, while it still has some protective power, it is overall less protective and durable to a penetrative sealer. It is easy to peel off and it's easier for water to get trapped underneath, which can cause mildew growth due to a lack of evaporation. It's best used in kitchens and backsplashes, but should be avoided in areas that are consistently damp.
Select Your Applicator Tool
Most grout sealers are in the form of an aerosol spray, but this isn’t always the most practical solution for sealing grout. For example, you may have glazed tiles that the spray won’t easily adhere to, so you’ll need an applicator brush or a grout sealer roll-on applicator bottle. If you have thin grout lines around unsealed tiles, opt for a sponge to cover large sections at once.
Apply the Grout Sealer
Working from left to right, begin applying grout sealer to your grout in small sections. Maintain close attention to every detail, taking care to cover the entire surface of the grout evenly. Use a dry cloth to wipe off excess sealer from tiles as you go.
Wipe the Excess Sealer
Wait 10 minutes for your grout sealer to settle, then use a dry cloth and wipe up the excess sealer residue from the surrounding tile. Sealer becomes difficult to remove when dry and letting it do so can leave your tile looking foggy.
Allow to Dry and Test With Water
Photo: Iarygin Andrii / Adobe StockAfter you’ve applied the sealer to your grout, allow it to dry for one hour. Then, drip a few water droplets onto the surface and see how it sits. If it beads up and doesn’t appear to penetrate, your sealer should be good to go. If it doesn’t, then you’ll need to apply an additional coat.
Apply a Second Coat, If Necessary
If water won’t bead up on your grout, apply a second coat of sealer and wait another hour for it to completely dry. Then, do another water droplet test—if it still doesn’t bead up, you may even need to do a third coat of grout sealer for full impermeability.
Aerosol Grout Sealers vs. Liquid Grout Sealers
Grout sealers come in two forms: Aerosol and liquid.
Aerosol Grout Sealers
Aerosol grout sealers come in a can, from which you can spray your sealant onto your grout. It's quicker and easier than applying liquid grout, which means it's good for quick jobs and can make reapplication easier.
However, aerosol sealers also spray broadly, meaning that you’re going to cover your tiles with the sealant and waste some of your product. It also applies thinly and you’ll have to apply more of it to be effective.
Liquid Grout Sealers
Liquid grout sealers usually come in bottles and are applied manually, like paint. While it's not as easy to apply, it allows for more precision and covers your grout in a thicker layer of protection. For most projects, liquid grout sealers are ultimately more effective.
DIY vs. Hiring a Pro to Seal Tile Grout
Learning how to seal grout is a fairly simple DIY, but it requires patience and attention to detail to do it well. If you’re not up for the task, you can enlist the help of a pro: The cost to seal your grout professionally ranges from $150 to $250 for 160 square feet. Get in touch with a local grout repair pro or handyperson for more details and a custom price quote.
Frequently Asked Questions
In almost all cases, yes. Most grout is cement-based, meaning it’s highly porous and susceptible to mold, mildew, and grimy deposits. Grout sealer is a crucial step if you’re looking to preserve the look and structural integrity of these types of grout. However, some types of grout—such as epoxy-based grouts—are not porous and do not need to be sealed.
If left to dry on tile, grout sealer can have a glossy or hazy appearance. You won’t be able to remove it with water or any basic cleaner; instead, you’ll likely need the help of a chemical stripper to get it off. It’s best to keep a watchful eye on your work while you’re applying the grout sealer, as it’s easy to remove with a cloth or sponge when it’s still wet.
Most grout sealers last one to two years before they need reapplication. If it’s in a wet area such as a bathroom or shower, be sure to reapply grout sealer at least once a year, if not more. Areas of your home that don’t see as much moisture or traffic can go up to two years before the grout needs resealing.
You can test whether your grout needs to be sealed with a water droplet test. If water beads up on the grout’s surface, it’s likely been sealed (or might not need to be). On the other hand, if the water gets absorbed or causes the grout to darken, then it’s time for a fresh grout sealing.
Yes, you can reseal grout regardless of its age. What matters is its condition: If you’re unable to clean or repair it effectively, sealing the grout will not restore its look. In cases of cracked or damaged grout, you’ll need to repair or replace it to ensure your tiles don’t shift around and create a safety hazard.
