How to deal with damp and moldy indoor walls and renovate them

Indoor walls that are damp and moldy can be treated by cleaning, removing mold, repairing the wall, moisture-proof treatment, ventilation and drying, and repainting. Dampness and mold are usually caused by factors such as humid environment, damaged waterproof layer, poor ventilation, pipeline leakage, and insufficient wall insulation.

1. Clean and remove mold

Use professional mold remover or diluted 84 disinfectant to wipe away mold stains. Stubborn mold stains can be repeatedly wiped with baking soda paste or white vinegar solution. Wear gloves and masks during operation to avoid inhaling fungal spores. After processing, use a dry cloth to absorb the moisture and open the window to accelerate drying. Be careful not to rinse directly with water, as it may expand the scope of mold growth.

2. Repair the wall surface

Remove the putty layer with peeling and hollowing to the firm base, fill the cracks with cement mortar, and add anti cracking mesh at the internal and external corners. The gypsum board with severe local mold needs to be replaced, and the wooden base needs to be sprayed with mold inhibitor. After repair, it is necessary to ensure that the moisture content of the base layer is below 8% before continuing construction, which can be detected by a moisture meter.

3. Moisture proofing treatment

Apply permeable waterproof coating to form a closed layer, and it is recommended to use polymer cement-based waterproof materials in heavy wet areas such as bathrooms. Waterproof mortar layer needs to be applied to the exterior wall due to water seepage, and sealant should be used to fill the joints around the window frame. A moisture-proof film can be added to the basement wall to form a closure with the ground moisture-proof layer.

4. Ventilation and drying

Install exhaust fans or fresh air systems to enhance air circulation, and use dehumidifiers to control humidity below 60% during humid seasons. Leave a distance of at least 5 centimeters between furniture and walls to avoid creating damp blind spots. Activated carbon or quicklime can be placed daily to absorb moisture, and windows should be opened for convection in a timely manner on sunny days.

5. Repainting

Use anti mold and antibacterial latex paint, and add anti mold agents to the coating to inhibit mold regeneration. Before construction, ensure that the base layer is completely dry and apply alkali resistant primer first. It is recommended to use diatomaceous earth with good breathability in the southern region, and waterproof and mildew resistant grout can be used to treat tile joints in kitchens and bathrooms.

Long term humid environments can easily cause respiratory diseases, and it is recommended to regularly inspect concealed pipeline interfaces. When decorating, priority should be given to selecting lightweight bricks, waterproof gypsum boards, and other materials with good moisture resistance, and moisture-proof pads should be placed on the back of furniture. During the rainy season, air conditioning dehumidification mode can be used, and dehumidification bags can be hung in the wardrobe. If the moldy area exceeds one-third of the wall surface or repeatedly occurs, professional personnel should be asked to check for any structural leakage problems in the building. Maintain a daily temperature difference of no more than 5 degrees Celsius between indoor and outdoor areas to avoid condensation. Watering green plants should avoid overflow, and water containers such as fish tanks should be placed away from walls.