How to Waterproof a Shed Roof

How to Waterproof a Shed Roof in Easy Steps

Our garden sheds are our pride. In fact, when some homeowners need undisturbed moments, they get to the shed for a little peace.

How to waterproof a shed roof is essential to learn because once rain seeps in, the interior will be dump, smell bad, and have molds. Additionally, water will damage the expensive equipment you store inside. Moreover, the area will be unpleasant to spend even a little time when you need some rest.

A good shed roof will protect your expensive equipment like lawnmowers, strimmers, and other garden tools. Further, your shed will last for years because most materials like wood that rot easily are protected. That aside, metallic sheets will not rust quickly.

In summary, waterproofing a shed roof is essential for your items. Thankfully, the exercise requires some simple products like silicone. On the other hand, a roofing substrate can also protect your roof. Read on to learn more.

How to Identify Leaking Areas on a Shed Roof

Check for leaks on the roof when it’s raining or immediately after the rain stops. Delaying after the rain has stopped can give you a hard time identifying the leaking points.

When inspecting the roof, check for dampness on the roofing area, discolored wooden bars, and drips coming from the ceiling.

Once you have identified the spots, you can mark them and repair rotten wooden bars before applying any waterproofing material.

How to Waterproof a Shed Roof: All the Requirements of Roofing

After meeting these requirements, you can later apply some waterproofing products. Take a look;

1. Choose the best roofing materials

Felt, shingles, and lightweight metal sheets are commonly used in shed roofing. They are water-resistant but have different life spans.

For instance, felt materials can last for around 10 years, whereas metal sheets can go for 25 years. However, this is the average estimation because different areas have different climates and weather, which can reduce their lifespan.

See also: How to install a shed felt roofing without nails

2. Choose the correct substrate

A substrate is a material that the roofing sheets are laid on. It protects the plywoods on the ceiling and other materials from water if it seeps in.

Applying a substrate will effectively protect the shed from rain and insulate the shed during the hot season.

However, ensure the roofing material fits well on the roof to direct the water where necessary.

3. Clean the gutters

Debris, dust, and leaves settle on the gutters, especially during windy seasons. As such, they clog the waterways, and once the water fills the gutter, it floods the roof.

Later, it will find its way inside the shed and cause damage. Ideally, clean the gutters before rain season and regularly during the season.

4. Clear Climbing Plants from the shed roof

Climbing plants spread on the roof and cause the water to flood once it rains. It’s wise to clear all climbing plants from the roof to protect the metal sheets from rusting and water seeping in.

5. Choose the best shed roofing design

Designs like skillion and gable have a good pitch that easily directs water to the gutters. A pitch of 4/12 is recommendable because it enables easy water flow even during heavy rains.

Additionally, snow will also flow easily during winter.

See also: How big of a shed can I build without a permit in texas?

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Gable Roofing Style

How to Waterproof a Shed Roof After Meeting the Above Requirements

With time, shed roofs can leak even after meeting the above requirements. For instance, metal roofing sheets may have rusted due to acid rains. In another case, bird poop can also quicken the rusting process.

With that said, you need first to treat rust on the metallic roofing materials before waterproofing.

Step 1: Removing Rust from Shed Roof

Use an extension ladder to climb and scrub the metal sheets with a stiff wire brush to remove the rust. You will have to wear a mask and glove because of the dust.

Start from one edge of the roof and scrub, moving downwards until most of the rusts clear.

However, if the material is much corroded, it may develop holes that cannot be sealed. In this case, you will have to replace the metal sheets.

After scrubbing, wash the roof with Trisodium Phosphate. Mix one cup of trisodium phosphate per one gallon of water and wash the roof.

Step 2: Apply Silicone Sealant

Insert the silicone caulk into the caulk gun and apply it to all leaking joints and holes. Also, apply on fasteners, nails, and screw heads and wait for around 24 hours before repainting.

Silicone caulk

Caulk gun

Ideally, carry out the process on a sunny day for the silicone to cover the leaking spots effectively.

Step 3: Paint the roof with metal roof paint

Apply primer before repainting the whole roof. We recommend Rust-Oleum Marine Metal Primer.

Afterward, open the metal paint canister and mix it according to manufacturer instructions. Most have particles that bind with the metal surface to form the best waterproofing coat.

However, it’s important to apply primer because some brands may not be much effective.

After mixing, attach the paint roller to the extension handle and apply from one edge while stepping on an extension ladder.

Start from the top, move downwards, and apply a thick layer.

See also: What is the best way to cool a metal shed

List of Best Shed Roofing Sealants

Applying quality sealant is the cheapest way to waterproof shed roof. Take a look at various sealants.

1. Everbuild Black Jack 901 Black Bitumen Paint 5 Litres

The blackjack sealant is my favorite sealant. It can protect corrugated iron sheets and is also good for timbers. It has proper adhesion, and it’s also easy to use.

2. All-Weather Roofing Compound Bitumen Waterproof Roof Coating 25 Litre

The sealant can be applied to alloy steel, iron, aluminum, and metals. All-weather roofing compound resists water immediately upon application.

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3. Aquashield by Britannia Paints Acrylic Waterproofing Roof Coating

Aquashield is compatible with alloy steel, fiberglass, and metal. It effectively seals the cracks and gaps.

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See also: Cheapest shed insulation diy

FAQs About How to Waterproof a Shed Roof

Should You Waterproof the Inside of a Shed?

You can waterproof the inside of a shed, but it will be much more effective after waterproofing the exterior.

See also: Best way to clean inside a wooden shed

Is Shed Roofing Felt Waterproof?

Felt is very effective in shed roofing. It offers waterproofing and protection from all weather.

What Should I Put on Top of My Shed Roof?

You can use materials like felt, shingles, or metal sheets. You can also add a substrate before laying the roofing materials.

With that said, waterproofing a shed roof can be easier with the above-recommended sealants.


  • Ricky

    Hi, I’m Ricky. I’ve been involved in lawn care and landscaping from when I was 15. To be honest, I didn’t like the idea of pushing mowers, collecting grass clippings, and maintaining flowerbeds at the time. But having seem the passion my parents had for gardening and outdoors and the effort they put in maintaining the health and beauty of our landscape, I couldn’t help but not only admire their hard work but also I became a part of it. As someone who loves to spend time with nature’s best, I find myself learning a lot more about gardening and outdoors on a daily basis. Not to mention I love to share the knowledge I’ve gathered over the years with my readers at We Mow Dallas. To be clear, I don’t have a Master’s degree in gardening or anything like that. Everything I’ve learned about gardening, landscaping, and lawn care spring from passion and engagement with my parents. And with a ton of free information out there, plus the ability to run tests and determine what works best for lawn care and landscaping, every day is an opportunity to learn and implement something new. My goal with We Mow Dallas is to teach you exactly how to maintain your lawn and landscape. And since I walk the talk in reality, you shouldn’t hesitate to join me in this wonderful world of landscaping and lawn care. K Beatrice

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