How much moisture is OK in walls

Zero moisture content in walls would be an ideal scenario, but it's not always realistic. Walls in residential and commercial buildings are exposed to moisture from a variety of sources, such as air leakage, water vapor diffusion, and capillary rise. As a result, it is not uncommon for walls to contain some moisture, even in well-maintained buildings. The key is to keep moisture levels within acceptable limits to avoid problems such as mold growth, structural damage, and unhealthy indoor air quality.

Acceptable Moisture Levels in Walls

The acceptable moisture content in walls is typically determined by the material used to construct the wall. For example, wood-framed walls can typically tolerate higher moisture levels than concrete or masonry walls. However, even wood-framed walls should not have moisture levels that exceed 15% to 20%. Concrete and masonry walls should have moisture levels below 10%. Contractors are equipped to test moisture in walls to determine if moisture levels are acceptable.

Consequences of Excessive Moisture in Walls

Excessive moisture in walls can lead to a number of problems, including:

• Mold growth: Mold can grow on any surface that is damp and warm. Mold can cause a variety of health problems, including allergies, asthma, and respiratory infections.
• Structural damage: Excessive moisture can weaken the materials used to construct walls, leading to structural damage.
• Unhealthy indoor air quality: Mold and other moisture-related problems can lead to poor indoor air quality, which can cause a variety of health problems.

Preventing Excessive Moisture in Walls

There are a number of things that contractors can do to prevent excessive moisture in walls, including:

• Properly sealing air leaks: Air leaks can allow moist air to enter walls, leading to moisture problems.
• Installing a vapor barrier: A vapor barrier can help to prevent moisture from diffusing into walls.
• Controlling capillary rise: Capillary rise is the process by which water moves through soil and other porous materials. Contractors can control capillary rise by installing a capillary break, which is a layer of material that prevents water from moving through it.

By taking these steps, contractors can help to prevent excessive moisture in walls and the problems that it can cause.