How to Stop Condensation Problems in Your Metal Building

How to Stop Condensation Problems in Your Metal Building

Condensation inside a metal building can be controlled with preventative measures and periodic maintenance.

Trapped moisture, also known as condensation, in the walls and ceilings of metal buildings can lead to corrosion and decreased insulation efficiency.  According to Richard Gebhart, senior technical manager, North American Technical Insulation at Owens Corning, “Metal is extremely conductive, allowing it to change temperature due to its surrounding conditions very quickly.” This conductive quality leads to condensation in pre-engineered steel buildings because the relative humidity inside the building is greater than the humidity outside the building. Relative humidity is a measure of how much water is in the air at a given temperature. Here are some ways to prevent relative humidity from turning into condensation inside metal buildings:


Have Vapor Barriers/Retarders Installed

A vapour barrier—technically a vapour retarder—is typically made of sheets of plastic or foil that prohibit moisture inside a steel building making its way into walls and insulation. Different kinds of vapour barriers have different degrees of permeability: impermeable, semi-permeable, and permeable.

A vapour barrier is only as good as its weakest point so properly installing, sealing and maintaining your vapour barrier is vital in preventing condensation from building up in your building. It’s also a good idea to keep the humidity level inside to a minimum, preferably below 40%. Avoid using moisture-rich temporary heat sources in the winter. Leaving large doors open to the exterior elements also increases your interior humidity levels.


Use Your HVAC System

The best practice to keep a metal building in Western Canada from accumulating excess condensation is by using a mechanical ventilation system or HVAC. Bill Beals, district manager at North Olmsted, Ohio-based Therm-All Inc., says, “Ventilation is best accomplished through the mechanical systems of metal buildings. Remember that steel buildings are a type of non-vented construction, which means the insulation systems do not allow for vented systems such as an attic-type roof.”

Figuring out the proper balance of insulation, interior surface temperature, interior air mixture and HVAC levels is key to preventing condensation. Achieving the proper balance has another variable: the weather.


Check Your Building in Winter

Balancing relative humidity in metal buildings is not as simple as “set it and forget it.” In the cold winter months, buildings have more condensation problems than in the warmer summer months. Increased condensation combined with freezing temperatures can lead to all sorts of problems. Check your building often for any water, frost or ice on windows, doors, frames, ceilings, walls, floor, insulation vapour retarders, skylights, cold water pipes and cooling ducts.

Look for concealed condensation by identifying damp spots, stains, mould or mildew on walls or ceilings, delaminated and laminated surfaces, bubbles in asphaltic surfaces, peeling paint and any damp insulation.

For more information, read What To Do When Your Metal Building Has Wet Insulation.


While pre-engineered steel buildings are built to last, they do require periodic inspections, maintenance and repairs. Metal Structure Concepts can help with scheduled maintenance for both pre-engineered and structural steel buildings all over Western Canada. Contact us to learn more.