Tackling Condensation In Your Garden Shed

A potential problem which is always worth considering when planning garden shed maintenance, is that some types of the shed are just likely to suffer from condensation – almost certainly if you live in the U.K. and don’t take the proper precautions in avoiding this issue before it rears its ugly head.

The types of garden sheds which are especially at risk of this particular mishap are metal sheds or vinyl clad but for practical purposes any material which would trap moisture and keep it contained without a clear avenue of escape.

Shed Condensation

Metal shed condensation is the same essential problem as condensation in any other enclosed area, namely: moisture gets trapped inside the shed and (due to a slight temperature difference which always exists between the inside and outside of a shed – i.e., the inside being slightly warmer) the moisture will begin a process of evaporation, until it reaches the coolest part of the shed (normally the roof, or windows) and then condenses into droplets and drips down to the floor again, therefore restarting the whole process.

The problem with this happening is, of course, that the process will, over time, damage the inside of your shed (as well as its contents) and also promote harmful mould and bacteria which you won’t want to be around for your health.

As a rule, the kinds of sheds which are most likely to suffer from this issue do tend to be self-assembly models. That of course, means that extra care must be taken during the assembly of the shed in order to nip this issue in the bud before it appears in the first place.

Things to Consider

There are various points about the overall construction of the shed to keep in mind when trying to avoid problems with condensation. Mostly they boil down to trying to ensure that everything is fitted together snugly and that no openings are left.

Roof and wall panels must be tightly secured in place, all screws, bolts, etc. must rest as snugly in their sockets as possible. Windows must be properly secured and insulated.

At the end of the day, the most fundamental and basic element of having your shed properly set up is establishing the base. Incidentally, the base is also very likely to prove the most important “battlefield” in determining whether your shed has moisture leakage or not.

Helpful Tips

Here are some simple tips in order to try and ensure that the shed’s base setup avoids any issues. All things being equal, the concrete base of a shed should only be slightly bigger than its base rails. For example, you can allow a size difference of perhaps just a couple of inches between the base and the rail measurement

Tip #1

All things being equal, the concrete base of a shed should only be slightly bigger than its base rails. For example, you can allow a size difference of perhaps just a couple of inches between the base and the rail measurement.

Tip #2

In order to really help keep any damp from setting in, the concrete base of your shed should rest completely on a damp proof membrane, without any areas exposed to soil or material which might easily become waterlogged. This way you will prevent moisture seeping up into the base and creating problems. Always remember that this is a step worth considering very carefully at the beginning of the process as you won’t be able to casually add one in later. Also keep in mind that if your shed’s base is below ground level, then the damp-proof membrane becomes redundant as moisture can seep in from the sides.

Tip #3

Whenever you lay a fresh concrete base which needs time to set, make sure that you allow it at least a week in order to harden and dry up sufficiently. Give it more time if you happen to be putting down the base in an already moist environment. An improperly dried base is the perfect fuel for beginning a condensation cycle with your shed, which you certainly don’t want to happen on the very first day the whole thing is set up.

Tip #4

When everything is set up and the shed is attached to the base, apply a good waterproof sealant to the base rails of the shed. Make sure, however, that this waterproof sealant is applied to the inside and not the outside of the shed’s base rails. Applying the sealant inside helps with future drainage of moisture, applying it outside has the opposite effect.

If you find yourself in the situation where condensation appears to be setting in, and you’ve already laid the foundation of your shed, one relatively quick, simple, and effective technique for dealing with the issue is to shift the shed from its base momentarily, then place a wooden raised platform (large enough to match the floor surfaced area of the shed) on the base and then place the shed on top of that platform.

The benefit of using this technique is that the wooden platform (if raised on sleepers) will allow for excellent drainage and not allow surface water to easily seep upwards to the floor of the garden shed.

This system also enables good airflow between the floor of the shed and the concrete base, which assists in drying out any moisture. Before resorting to this solution, make sure that you use a wooden platform which is strong and sturdy enough to hold the weight of your shed comfortably.


Please note that this guide is intended to present general information regarding the subject. All information indicated are representative and not exhaustive which means that the results may vary depending on your item, its size, complexity, and other circumstances. You may or may not follow the guide. By following the guide, you accept the risks and acknowledge the possible invalidation of your manufacturer’s warranty. When in doubt, please ask your manufacturer before proceeding.

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