How much moisture is OK in walls? Moisture intrusion is a leading cause of structural damage, and even small amounts of moisture can eventually lead to serious problems. The amount of moisture that is acceptable in walls depends on a number of factors, including the type of material used to construct the wall, the climate, and the amount of ventilation. Generally speaking, the following guidelines can be used: - For wood-framed walls, the moisture content should not exceed 15%. - For masonry walls, the moisture content should not exceed 5%. - For concrete walls, the moisture content should not exceed 4%. If the moisture content of a wall exceeds these levels, it is important to take steps to identify and correct the source of the moisture intrusion. This may involve repairing leaks, improving ventilation, or installing a dehumidifier. Failure to address moisture intrusion can lead to a number of serious problems, including: - Mold growth - Rot - Structural damage In severe cases, moisture intrusion can even lead to the collapse of a building. If you suspect that your home or building may be suffering from moisture intrusion, it is important to have it inspected by a qualified professional. Early detection and repair of moisture intrusion can help to prevent serious damage and costly repairs.