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  • What causes condensation?

    Condensation in your shed is caused when the outside is cold and the inside is warm. As the temperature outside gets colder, so does the fabric of your shed (metal in this case).

    This is because metal sheds are usually made from thin, heat-conductive sheets. When it’s cold enough, it reaches what we call a ‘dew point’. This is Does my shed need a vapour barrier Garden Buildings Direct infographic with three tiles for different sheds and climates with icons and arrows regarding air flow, insulation, and vapour barriers

    Use this infographic to decide if your wooden shed needs a vapour barrier.

    Got it? Great. Now let’s have a look in detail at just how those steps will help keep your metal garden shed moisture-free.

    Anti-condensation Roofing Sheets 

    If you’re wondering how to stop condensation on steel roof sheets, we’ve got you covered. If you’ve got a large metal shed, condensation on the roof can be a real killer.

    So what you need to do is find a way to absorb moisture and keep water away from your roof. This will help you prevent rust and damage to your metal shed. 

    A good place to start is by constructing a roof with anti-condensation roofing sheets. These work by absorbing and retaining any moisture until it’s hot enough to evaporate. Plus, metal roof sheets form natural gullies to get rid of run-off water.

    But you might still want to protect the underside of your shed’s metal roof. And we can’t blame you.

    So to do that, we suggest using a spray cavity filler. A closed-cell polyurethane spray foam will help prevent condensation from forming.

    You can also apply polystyrene tiles to help insulate your roof. To prepare to treat the underside of your metal roof:

    Just check out how the guy in the video below does this:

    Having good airflow through your metal garden shed will ensure that areas can’t get damp. It’ll also help to regulate the difference in temperature between your shed and outdoors.

    You can always improve ventilation by simply opening windows (or skylights if you have them). This can also help to reduce condensation between double-glazing. But this is a time-consuming and short-term approach.

    You might be better off installing wall vents in your metal shed’s eaves. Or, you could even install a whirligig or an electric fan if you’re hooked up to utilities. 

    To help with this, you could also use a moisture trap or dehumidifier in your outdoor garden building. This will help to remove water from the air in your shed so there will be less chance of it forming as condensation.


    Another tip for dealing with condensation in a metal shed is to create a tight seal. Ventilation can help with airflow at the top of your shed. Then caulking can deal with moisture at the base.

    After bolting your metal shed to a concrete slab or base, make sure to caulk the inside around the base. Use silicone or a mastic sealant around the inner rails. This can ensure that groundwater doesn’t seep into your metal shed.

    From there, you’ll be ready to combat condensation on the outside of your shed.

    Interior of large metal shet with light coming through roof vent

    Should I Still Buy a Metal shed? 

    The short answer is – well, yeah! 

    Don’t let this guide fool you – we’re here to help solve problems and buying a metal shed solves more than it creates. They’re practical and durable. Plus, they’re lightweight and come at an attractive price point.

    Just make sure you follow the steps laid out in this guide. Then you can combat condensation before it even occurs.

    Let’s recap:

    • Choose appropriate roof cladding
    • Seal and insulate your shed
    • Build on an appropriate, dry base
    • Install ventilation or aerate 
    • Use a dehumidifier
    • Check tools and contents regularly for damp
    • (Optional) Fix polystyrene tiles to the roof

    Then you should have no problems at all.

    And if you do opt for a metal shed, you’ll overcome a lot of the maintenance problems associated with timber sheds. It’s horses for courses, though. The only reason you tend not to get condensation in timber sheds is that there are natural gaps in the joins.

    So if you want an air-tight metal shed that’s durable and easy to build – make sure to seal the base and bolts!

    And if you’re still not sold, check out this handy guide on the advantages of metal sheds.

    Shop Metal Sheds


    The best stage at which to combat condensation is before you even build your shed. If pouring a concrete base, make sure it isn’t much wider than your shed base. Otherwise, it’ll draw excess moisture. Also, allow the concrete to set and dry sufficiently. 


    Otherwise, you can use a ventilated and insulated wooden base. We also suggest adding vents to your eaves. You can even use anti-condensation roof sheets, caulking, and insulation spray. These will all help regulate temperature and keep a tight seal. Then finish off with a humidifier.

    Double-glazing will help to regulate indoor vs outdoor temperature. Then, installing air vents or opening windows can help to stop moisture from forming.

    Yes, unlike timber sheds. But it’s nothing to be afraid of. The positives of metal sheds (price point and durability) far outweigh a bit of condensation!


    Read back over our helpful guide to stopping condensation for more info.

    If you’re working in your metal shed or using it as a storage shed, chances are it’ll be warmer than outside. But this doesn’t have to be a problem. What you want to do is regulate temperature rather than simply make your shed cool.


    To do this, install ventilation and use a dehumidifier at the very least.

    A lot of guides will tell you to use insulation paint. But for stopping condensation, this won’t solve your problems. Plus, a shed’s rail frames make it hard (or impossible!) to install wall and roof insulation batts. 


    Instead, we suggest using an insulation spray on the underside of your roof. If bolting your rail base down, make sure to caulk on the inside and around bolt holes. Then you can also affix polystyrene tiles to the underside of your roof.