One common occurrence noticed by metal shed owners is condensation appearing in their sheds. They often want to know what causes this, and how to stop it. Condensation in your metal shed can cause issues if you are storing dry items such as seed or fertiliser, or electrical items such as a lawn mower or hedge trimmer.

What causes condensation in my metal shed?

Condensation occurs in metal sheds as the air inside the shed is slightly warmer than the air outside the shed. Because of this, any moisture currently within the metal shed or its foundations will rise up until it hits the cold steel of the shed’s walls, when it condenses into water droplets. Once this cycle gets underway, it can be difficult to put a stop to.

How can I get rid of condensation in my metal shed?

There are two ways to clear the condensation inside your metal shed:

Remove the metal shed from its base, and build a timber base from raised bearers. Ideally this base should be a few inches larger than the base of your metal shed to aid stability. Fix the shed to the wooden floor using both wood screws and mastic seal on the inside of the shed base rails, thus allowing the air to flow underneath the building. This should prevent the build up of moisture, although you should make sure that no water is able to pool at the bottom of the shed.

The second option is to firstly dry off your metal shed until all of the moisture has been cleared, and clean the underside of the metal shed’s roof panels using meths or an equally effective cleaning agent. Once the roof panels are dry again, stick polystyrene tiles to the underside of the panels. This method will not take the moisture out of the air, but it will prevent it from condensing and dampening the inside of your metal shed.

Preventing condensation in your metal shed

Prevention is, of course, the best cure, and you can prevent the build up of condensation in your metal shed when you construct the shed base.

A concrete or slab base for a metal shed should only be a few inches larger than the base of the metal shed. Then insert a damp-proof membrane, which should be around 2 inches higher than the surrounding ground. Damp-proof membranes can be purchased from DIY and hardware stores relatively cheaply, and are usually based around a polystyrene sheet or polyethylene base. Once you have bolted your metal shed down, you need to seal around the inside of the base. Mastic sealant is generally recommended, although cheaper alternative such as putty can be just as effective.