Condensation Problems in Metal Buildings

Condensation appears as drops of water grouped together.

Evidence of liquid water in metal buildings is often mistaken for leakage from roofing failure. However, condensation is a common, and potentially serious, culprit. Evidence of excess condensation may include musty odors, mold and mildew growth and deterioration of building materials.

Causes

Condensation occurs when warm air comes in contact with cold surfaces. Warm air, which holds more moisture then cold air, loses its ability to do so when it comes in contact with a cool surface. This results in the sudden release of excess moisture in the form of condensation. This is perhaps most noticeable on home windows, but can occur on almost any surface, including framing members and metal roofs.

Problems

Some condensation is normal. However, excess condensation can cause a host of problems. For example, excess condensation can decrease the effectiveness of insulation, cause mold and mildew to grow, produce a musty odor, cause wood rot, and encourage insect infestations. With respect to metal buildings in particular, condensation can cause rotting of timbers, and corrosion of metal decking, metal roof panels and metal fasteners.

Solutions

Solving condensation problems in a metal building varies depending on the specific cause. In general, most condensation problems an be avoided by keeping the relative humidity in the building between 30 and 50 percent. This an be done by running a dehumidifier with a hygrometer, designed to read the relative humidity. Other solutions for controlling condensation include installing vapor barriers and insulation, increasing air circulation and ventilation and fixing leaks promptly.

Special Considerations

Mold and mildew are the most dangerous problems associated with condensation due to the health problems they may cause, including asthma attacks and other respiratory problems. If you are experiencing significant condensation problems, there is a good chance that mold and mildew growth has already begun to occur, even if you cannot yet see the mold or mildew. Consider hiring a professional to check for and remove mold and mildew growth.

References

• Metal Building Depot: Condensation Control
• Metal Construction Association: Controlling Condensation in Steep Slope Metal Roofing Systems
• Environmental Protection Agency: Controlling Moisture