How Do You Keep Mould Out of a Wooden Shed?

How Do You Keep Mould Out of a Wooden Shed?

Avoiding Mould & Condensation In Your Garden Shed

Your shed is continually exposed to the elements and is seasonally at risk of mould taking hold. However, there are a number of ways you can protect your shed, particularly wooden sheds, from falling foul of mould.

Preventing mould from taking hold is key as it can cause a number of serious issues for your shed, including -

  • Causing wood to warp
  • Adhering to walls and rooves
  • Damaging stored items
  • Causing wood to rot

Here are a few ways you can help to damp proof your shed and keep mould at bay.

how to avoid mould in your shed

Prevent Rising Damp

One of the ways that mould can start to grow in sheds is as a result of rising damp. Rising damp occurs when excess ground water is then absorbed by surrounding structures, especially wooden sheds. Preventing your shed from taking in this excess water is simple to do, but it is preferable to do so before you construct your shed.

This is because rising damp gets in from the ground up, so putting in place a secure barrier or base is the only way to prevent it. It is of course possible to move your shed onto a different base structure if the issue of rising damp persists. Great damp-proofing shed base options include -

  • Paving slabs and concrete - these prevent pooling water
  • Gravel - this material helps rainwater to disperse properly
  • Timber bearers - these allow the shed to be lifted away from the ground to prevent water being absorbed

With so many different material options, it is now easier than ever to find the best rising damp solution for your shed.


Treating the exterior surfaces of your shed is also a great way to prevent any mould from building up and causing a nuisance. Most hardware shops sell wood treatments, so it's easy to get your hands on a tin or two.

Simply paint on all exterior walls, including any doors, to keep your shed in the best condition. Treatments to your shed should ideally be done on an annual basis and come in a variety of colours and stains, so you can create the ideal aesthetic for your garden shed with these too. Bonus!


Along with treating the exterior walls of your wooden shed with the right treatments, it is also important to seal any windows too. Of course, not all wooden sheds will have windows, but if yours does, then they could provide an easy access point for draughts and damp to seep through.

Using a silicone sealant product can help fill in any surface cracks, helping to prevent any mould issues from developing in the future.


Now that you've taken care of the outside of your shed, it is time to make sure that the interior is protected too. Ensuring your shed has the right insulation is key as condensation can play havoc with the inside of sheds.

This is because as the temperature falls, cold surfaces are at risk of getting wet, which provides the perfect condition for mould to fto flourish. This can lead to damage to the contents of your shed, as well as to the wooden structure of the shed itself.

By insulating the inside of your bike shed, you are ensuring that the temperature stays roughly the same, preventing any sudden temperature drops. There are plenty of different types of insulation materials to choose from, along with a variety of thicknesses too.


Proper ventilation is also vital when it comes to protecting your shed from a build up of mould. Even opening the door or windows of your shed once a week can really help to replace stale air with fresh air.

Although this can be harder to do in the winter months, it is important not to let stagnant air circulate continually in your shed. Good ventilation is key when it comes to preventing damp from building up. You may also wish to consider the idea of installing vents, ideally one on each side of the shed, in order to keep air flowing continuously.

Be Vigilant

It may sound like an obvious solution, but staying vigilant to the signs of damp can help eradicate any mould that may appear, as well as preventing it from happening in the first place.

The roof is probably the most vulnerable area to changing weather conditions, so be sure to ensure this surface is waterproof and covered with a durable material, such as felt. Using a rubber sheeting material underneath can also help to provide an extra layer of protection too.

Remember to keep an eye out for any cracks that might appear in wall panels or window frames. If you do spot any problem areas, be sure to act promptly in order to prevent the issue from getting any worse.