Scientists have discovered that mold appeared around 200 million years ago. The fungus survived droughts and the Ice Age. Traces of mold are found even in areas with high radiation levels, where other organisms cannot survive. Therefore, it is not surprising that mold can appear in the grout between tiles.
This guide aims to help you get rid of mold using simple ingredients and to prevent you from getting mold in the future.
Causes of Mold in Grout
- High Humidity
The humidity levels in tiled rooms are usually high. This environment creates favorable conditions for the growth and reproduction of fungal organisms.
- Predominance of Artificial Lighting
Most bathrooms do not have large windows, so they rely solely on artificial lighting. Unlike artificial light, natural light suppresses the viability of mold and other harmful microorganisms.
- High Temperature
Increased air temperature is an optimal condition for fungal life forms.
- Gaps, Cracks, and Chips in Tiles
Water accumulation in such places always facilitates mold growth.
- Air Stagnation
The absence of windows and insufficiently effective ventilation are additional factors contributing to mold development.
Signs of Mold in Grout
- Gray and Black Mold: This appears as dark spots on the surface. In the early stages, the mold is colorless, making it almost impossible to detect.
- White Mold: Looks velvety and has a fibrous coating.
- Green and Blue Mold: Has a heterogeneous structure. It is easily visible in light-colored grout lines.
- Red or Pink Mold: Appears as a fluffy surface with a light matte (soapy) coating.
What Harm Can Mold in Grout Cause?
In addition to an unpleasant interior appearance, mold can lead to unpleasant symptoms in humans.
- Skin rashes
- Cough
- Feelings of lethargy and weakness
- Chronic runny nose
- Allergies
- Chronic headaches
- Conjunctivitis
Preparing to Clean Mold from Grout
There are many products available for cleaning mold from grout. However, regardless of the chosen product, certain safety measures must be taken first.
- Use Rubber Gloves: Always wear rubber gloves while working.
- Wear Protective Gear: It is also advisable to use a respirator or mask and safety glasses. If there is a lot of mold, consider using replaceable or disposable clothing (like a raincoat).
Before starting, remove all unnecessary items from the room. If this is inconvenient, cover them with a thick plastic sheet.
Work only with closed windows and turned-off fans and air conditioners. Otherwise, mold spores can spread throughout the room with the airflow.
How to Remove Mold from Grout
Homemade Remedy with Baking Soda and Peroxide
Use the following ingredients.
- Baking Soda – 4 parts
- 3% Hydrogen Peroxide – 3 parts
- Dishwashing Liquid – 1 part
Using a regular toothbrush or a dish sponge, apply this mixture to the grout lines and leave it for 2-3 hours. Then, scrub the grout with a toothbrush. This method is suitable only for white grout and is not recommended for colored grout.
The mixture of baking soda and vinegar is one of the most effective natural ways to remove mold. You can find detailed proportions, step-by-step instructions, and safety recommendations in our guide on using vinegar and baking soda to remove mold.
Homemade Remedy with Baking Soda and Vinegar
For this remedy, use a large container, as the interaction of baking soda with acids creates a lot of foam.
Use the following ingredients
- Water – 7 cups
- Baking Soda – ½ cup
- White Vinegar – ¼ cup
- Lemon Juice – ⅓ cup
Mix all the ingredients and apply the mixture to the grout using a toothbrush. Leave the mixture on for 2 hours. After that, rinse the cleaning solution with water and wipe the grout with a cloth.
Some homeowners also try using ammonia for stubborn mold spots on tiles. Our guide on whether ammonia kills mold explains how it works, when it’s effective, and what safety precautions to follow before using it.
Chlorine-Based Homemade Remedies for Cleaning Grout
To clean mold from tile grout, make a paste consisting of equal parts bleach and baking soda. Mix them into a thick paste, apply it to the grout with a spatula, and wait for it to dry. Then, gently rinse the mixture off with warm water using a brush.
Keep in mind that chlorine-based remedies are effective only in the early stages of mold development.
Professional Chemical Mold Removers
- RMR-86 Instant Mold and Mildew Stain Remover Spray
- MOLD ARMOR Mold and Mildew Killer
- Concrobium 25326CAL Mold Control Spray
- Household Black Stain Gel
Apply any of these products to the grout with a sponge, wearing gloves, and leave it on for several minutes. Then, rinse with clean water and scrub the heavily stained areas with a brush.
Make sure to always read and follow the instructions before using these products to get the best results.
Cleaning Grout with a Steam Cleaner
To clean the joints between tiles, use a pinpoint nozzle with a round brush attached. The combination of steam and mechanical friction removes even the toughest stains. After steam cleaning, dry the surface with a cloth. However, be cautious when cleaning silicone-sealed grout—only brief steam treatment is appropriate in this case.
Removing Grout
If the methods mentioned above do not work, getting rid of mold may take more time. You will likely need to $$$remove the old grout and regrout the joints.
Final Thoughts
Mold in grout is a sign that your bathroom needs better moisture control, not just more cleaning. After removing visible mold, focus on long-term solutions: use a working exhaust fan during and after showers, keep the door open when possible, and dry wet surfaces with a towel. In humid areas, adding a small dehumidifier can make a big difference.
With these simple habits, you can significantly reduce the chance of mold coming back—without constant scrubbing or inspections.
Once you’ve cleaned your grout and removed all traces of mold, it’s important to protect it from coming back. Our guide on how to protect grout from mold, stains, and damage explains how to choose the right grout sealer and apply it properly to keep your tiles fresh and mold-free for years.
