Preventing condensation from forming in your metal tool shed

November 27th 2001

I have a metal tool shed. During the winter months the inside of the shed is completely saturated with moisture and has caused bikes to rust and the seats to become moldy. Is there anything I can do to stop the condensation from forming?

1. Any uninsulated metal building or building with an uninsulated steel roof such as porch canopies will have condensation form on the underside during cold weather. These must be insulated.

2. Any enclosed building with metal sides or metal roof or metal garage doors must be properly ventilated to allow warm moist air to escape. If not condensation will form.

3. Moisture forming on the inside of metal walls or roofs is the first indication of excessive relative humidity.

4. Metal buildings exposed to bright sunshine on east facing lots will be most affected on cold bright mornings because of the radiant heat of the sun warming the building.

5. Metal buildings are most effective in cold dry climates not in damp coastal areas ie. Vancouver.

To insulate strap the inside of the building, then apply rigid foam insulation minimum 1 inch thickness. Allow for ventilation to the outside by cutting holes through the foam insulation and metal wall during application. Vent size should be 6" diameter, front and back of an 8' x 8' building.

Finish the inside by applying thin plywood wall paneling over the foam insulation doing both walls and underside of roof. If you prefer you can also use the rolls of reflective foil insulation such as Reflectix.

If your shed is 700 square feet or less, you can control the moisture level by installing a WizzVent which can easily be installed and you plug into a 115 volt outlet.
Simply set dehumidistat control (on unit) to required moisture level depending tempertures outside and it will come on automatically when needed to maintain the appropriate moisture level. For more information you can visit or call them directly 1-888-430-2244