Dark grout may leave your kitchen or bathroom looking dirty, even after cleaning the tile. Grout is porous and tends to collect dirt, mold, and other types of debris, which leads to discoloration.
Grout is also available in a wide range of colors. If you start with a darker color, you may eventually decide that a lighter color may look better.
Use the following steps to restore dirty grout or lighten dark-colored grout to a lighter shade.
How to Lighten Tile Grout in a Bathroom or Kitchen
Inspect the condition of the grout before attempting to lighten its color. If the grout is already showing signs of cracking, you may want to consider regrouting.
Aggressively cleaning or bleaching the grout may worsen its condition. For grout that appears in good condition, you can lighten the color using one of the following methods:
Cleaning and bleaching can help restore the condition of dirty grout that was previously a light color.
For example, white and off-white are the most common colors of tile grout. White and off-white also darken easily.
Cleaning the grout can remove dirt and debris while bleaching helps lighten stains. Bleaching may also help lighten darker grout.
Instead of white or off-white, your bathroom or kitchen may feature darker grout to match or contrast the color of the tile. You can bleach darker colors to achieve a lighter shade.
You can also paint grout. However, you need a special type of paint designed specifically for grout.
Grout colorants allow you to essentially stain the grout a lighter shade. Yet, colorants work best with medium to light shades of color. Darker shades may lighten slightly but some of the original colors will likely show through.
Here is a closer look at each method for lightening dark grout.
Lighten Dirty Grout Using Baking Soda, Vinegar, and Ammonia
If the grout has darkened due to dirt and debris, you can attempt to scrub the grout clean using a combination of baking soda, vinegar, and ammonia.
Mixing baking soda with vinegar releases carbon dioxide, which helps lift dirt. Baking soda and ammonia also help break down dirt, grime, and grease.
Combine a one-half cup of baking soda, one-third cup of ammonia, and a one-fourth cup of vinegar with seven cups of water. Stir the mixture.
You can apply the mixture using a rag or a spray bottle. Apply liberally, allowing the mixture to coat the grout.
Let the mixture sit for several minutes before scrubbing with an old toothbrush or a small brush. Brush in circular motions.
Rinse and wipe the treated area. If the grout is not lighter, try reapplying the mixture and allowing it to sit for an hour or overnight.
Repeat the cleaning process until the grout looks new and shiny.
Clean Dark, Dirty Grout with Powdered Oxygen Bleach
Powdered oxygen bleach is an effective stain remover that may lighten dirty tile grout. Oxygen bleach releases oxygen when exposed to water, which helps lift stains and debris.
Use the manufacturer’s instructions to combine the powdered bleach with water. Spread the mixture over the grout lines.
Allow the oxygen bleach mixture to sit for at least 15 minutes. You may want to wait longer for exceptionally dirty grout.
Scrub the grout using a toothbrush or small brush. Rinse the grout and wipe it dry.
Scrub Dark Grout with White Vinegar for a Lighter Look
White vinegar is commonly used to clean dirty tile grout. Vinegar is acidic, which helps dissolve soap scum and other dirt in the grout.
White vinegar is an effective cleaning agent, but it can damage certain materials. Do not use vinegar when cleaning grout between stone floor tiles, as the acids may discolor portions of the tile.
Vinegar is best suited for cleaning grout from between ceramic bathroom and kitchen tile.
Pour vinegar over the grout and allow it to sit for 10 to 15 minutes.
Scrub the grout using an old toothbrush or a small brush. Wipe the area clean to check if it requires more cleaning.
Bleach Tile Grout to Achieve a Lighter Look
If the tile grout was originally a darker color, the previous methods may not help lighten the grout. Grout is available in a wide range of dark colors to suit different styles, such as dark blue or dark green.
To lighten grout that contains darker pigments, try bleaching the grout. Bleach is often used to lighten the color of various materials, including fabrics and hair.
Chlorine-based and peroxide-based bleaches produce an oxidizing action that reduces the bond with color compounds. However, using bleach to lighten grout requires specific supplies and steps.
You will need gloves to protect your hands from the bleach. You also need a bucket to hold the bleach, a brush to scrub the grout, and a cloth or rag to wipe the grout dry.
Start by putting on gloves. You should also turn on any fans or open windows to increase the ventilation in the room you are cleaning.
Use a bucket to mix one part bleach with five parts of water. For example, if you use one cup of bleach, add five cups of water.
Dip the brush into the diluted bleach and scrub the grout using a circular motion. Continue to scrub for several minutes and allow the bleach to sit for 10 minutes.
After allowing the bleach to sit, rinse the grout clean with water and wipe it dry. If you are not happy with the results, you can repeat the process to lighten the grout further.
Bleaching works well with off-white grout and other colors that are not deeply saturated. You can typically lighten the grout several shades without any other steps.
Another option is to use a bleach pen. Instead of diluting liquid bleach, you rub a bleach pen across the surface of the grout.
The bleach pen helps eliminate stains and lightens darker grout.
Unfortunately, bleaching does not work well on very bright colors. Bleaching bright colors increases the risk of uneven discoloration.
If the existing grout is heavily colored with bright pigments, try using a grout colorant to achieve a lighter color.
Can You Use Undiluted Bleach on Grout?
Undiluted bleach may harm the grout. Diluting bleach with water is necessary for limiting its strength.
Pouring undiluted bleach on the tile grout may cause uneven or unusual discoloration. Some areas of the grout may appear lighter. You may also notice lighter spots.
In some cases, the bleach may alter the hue of dyes. A blue dye may appear orange or green instead of a lighter shade of blue.
Undiluted bleach may also weaken the grout. Weakened grout is more likely to chip or crack.
Use Grout Colorant to Lighten Darker Colors
Standard acrylic or latex-based paints may not work well on tile grout. The paint is likely to chip, crack, or peel easily.
If you want to attempt painting tile grout, only use products designed specifically for grout.
Grout colorants are typically epoxy paints. The epoxy adheres to the grout and should last for years.
Before applying the colorant, thoroughly clean the grout. You may want to use one of the three DIY cleaning methods described earlier.
Using a baking soda mixture, vinegar, or oxygen bleach helps remove dirt and debris that may keep the epoxy from adhering to the grout.
After cleaning the grout, allow it to dry thoroughly before applying the paint.
Old toothbrushes and small hard-bristle brushes are often used to apply grout colorants and stains. The product is scrubbed into the grout.
Do not worry about getting colorant on the surface of glazed tile. You can easily wipe the tile clean using a damp cloth after the colorant dries.
Along with lightening the grout, colorants help seal the grout to protect against future stains and discoloration.
Can I Put New Grout Over Old Grout?
Applying a lighter grout on top of a darker grout may lead to several problems. The new grout may not properly adhere to the tiles or the existing grout.
Adding new grout may also fail to fully cover the darker grout. You may need to apply a thin layer, allowing the older grout to show through.
Adding grout on top of old grout may also conceal dirt and mold. Mold can continue to spread while dirt may limit the strength of the new grout.
Instead of adding new grout on top of old grout, remove the old grout first.
Remove and Replace Grout with a Lighter Shade
If the previous methods do not work, replacing the grout (regrouting) may be your only option.
Regrouting involves two main steps. You need to remove the old grout and apply new grout in the color of your choice.
You can remove the grout manually or with a power tool. Common options include an oscillating tool or a handheld rotary tool with a blade designed for grout removal.
You can also find manual grout removal tools. Using a manual tool involves more work, which may be a challenge when attempting to remove grout from an entire bathroom or kitchen.
Whether you use a power tool or a manual tool, use caution when working near the edges of the tile. Grout removal tools can easily scratch or crack the surface of the tile.
You will also likely need to complete several passes with a grout removal tool or blade. During the first pass, you simply want to remove the bulk of the grout.
You should also stop occasionally to clean up the dust and debris. Maintaining a clean work area makes it easier to monitor your progress and avoid scratching the tile.
After removing the bulk of the grout, perform a second pass with your grout removal tool or blade. Attempt to remove any remaining chunks.
Use a utility knife or screwdriver to clean the grout lines. The remaining grout should crumble easily.
Thoroughly vacuum the grout to clean up any remaining debris. You can now apply the new grout.
Apply a Grout Sealer After Lightening the Color
Grout requires periodic resealing to protect against dirt and grime. You should also apply a sealer after lightening the color with bleach or a colorant or cleaning dirty grout.
Sealing the grout helps keep it from darkening and shields against future stains.
Tape off nearby surfaces before applying the sealer. Use a foam paintbrush or small roller to coat the grout lines.
Apply a thin coat and allow it to dry for about 15 minutes before applying a second coat. Use a damp cloth to wipe off any sealer that gets on the tiles.
How to Keep Grout From Darkening
Wiping the grout lines clean once or twice per week should help prevent mold growth and keep the grout from darkening too quickly.
A standard multipurpose surface cleaner can help kill mold and bacteria. Simply spray the cleaner over the surface of the tile and grout and wipe clean using a dry cloth.
Grout also typically requires deep cleaning once or twice per year. Deep cleaning involves scrubbing the grout with a narrow brush or old toothbrush.
You can use commercial grout cleaner or DIY cleaning mixtures to help lift dirt and stains. The cleaning agent typically needs to sit for several minutes before you start scrubbing.
Depending on the size of the bathroom or kitchen and the amount of moisture, you may need to clean the grout more frequently. Poor ventilation and water from sinks and tubs can promote mold and bacteria growth in the grout, leading to black buildup.
The method that you use for lightening dark grout depends on its original color.
If the grout was originally a dark color, you may need to use bleach or a grout colorant to lighten the color. However, the most effective solution is to remove the old grout and add new grout in the color of your liking.
If the grout was originally white or a light color, you may simply need to clean and reseal the grout to restore its lighter color.
I have a bachelor’s degree in construction engineering. When I’m not constructing or remodeling X-Ray Rooms, Cardiovascular Labs, and Pharmacies…I’m at home with my wife, two daughters and a dog. Outside of family, I love grilling and barbequing on my Big Green Egg and working on projects around the house.