5 Simple and Practical Tips on How You Can Waterproof a Shed

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Waterproofing your shed protects both the shed itself and its contents from water damage. Too much moisture causes wood to rot, leading to the buildup of mold and mildew and rust on metal tools. Whether you built your shed for storing tools or creating a garden shed, this article will outline the steps on how to waterproof it.

1. Build a Base

Your garden shed will last longer and stay in better condition if it is built on a base rather than sitting directly on the ground. You can either make your own base or buy an eco-friendly alternative, the plastic shed base. 

Both concrete and plastic bases will help waterproof your shed and keep it clear from groundwater seepage. You can also use a waterproof membrane for your shed base for even better waterproofing. The best plastic base kits also boast waterproofing features.

2. Apply Wood Preserver or Waterproof Shed Paint to the Shed

It’s essential to treat your shed’s walls with wood preservatives at least once a year, even if your shed comes with a 20-year guarantee. Dip-treated sheds may be protected during transit, but the wood will weaken over time if left untreated. 

By treating your shed with a high-quality shed preservative, you can help protect it from the elements and extend its lifespan.

If your shed walls are getting wet inside, it could be because there are holes or gaps in the walls or roof that let in the rain. If you find any gaps or holes, you may be able to seal them with waterproof sealant.

Condensation may not be a problem if your shed is made of wood. That’s because wooden sheds are less airtight than metal sheds, making it easier for warm air to escape.

3. Seal the Base

The first step to sealing a shed base is to add sealant between the concrete and the shed frame. This limits moisture transfer and prevents it from being absorbed into the concrete.

You also want to seal the base of your shed from the inside. For example, some shed bases have metal channels. If you seal these from the outside, water may be trapped in these channels and cause rust, rot, and mold.

Additionally, if you seal your shed base from the inside, water can’t also get into the channels as quickly. The joints at the corners and drainage holes give moisture a way to escape, keeping it away from the structure.

4. Insulate the Shed

Shed insulation is a crucial factor in protecting your outbuilding from dampness. By regulating the temperature and keeping it above the dew point, insulation can also help waterproof your shed.

5. Waterproof Your Roofing 

One of the practical ways to waterproof a shed roof is to lay green mineral roofing felt. It’s inexpensive yet effective to ensure your shed roof is waterproof and will stay that way. The finish is designed to prevent mineral separation, which can help prolong the lives of your shed and its roof.

Gutters also help prevent puddles around your shed, which could cause flooding. Ensure to clear your gutters of leaves and other debris. 


Waterproofing your shed is important to preserve its quality. If you are planning to waterproof your shed and want to do it the right way, you should ensure you have the basic knowledge outlined in this article. 

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