How to Waterproof a Canvas Boat Cover

Having a canvas boat cover is convenient until it starts to rain and you find out that the cover is letting water inside the boat, leaving you with a huge mess you have to deal with. If this sounds familiar, this post is for you!

boat covered in blue canvas boat cover

We’ll be covering some of the most effective tips and tricks for waterproofing your canvas boat cover, from waterproof spraying to good-old waxing, so stick around. 

1. Clean the Cover Thoroughly

The first step to waterproofing your canvas boat cover is to make sure the cover is as clean as possible.

The cleaner the cover, the more effective and long-lasting the waterproofing will be. 

To clean the canvas cover correctly, here’s what you need to do:

  1. Hose the canvas cover.
  2. Scrub it with a soft brush and a detergent. Avoid using harsh detergents; ivory would be a great choice.
  3. If there’s a persistent stain that’s hard to clean, you can soak that spot in a gallon of warm water along with half a cup of chlorine bleach and a quarter of a cup of detergent.
  4. Don’t use hot water or it will ruin the canvas.
  5. Let the cover air-dry after you’re done.

2. Use a Waterproof Spray 

Now that you have a clean, dry canvas cover, let’s start with the waterproofing process.

The first option is a waterproof spray.

What Type of Spray to Use

The safest spray option to use on acrylic canvas is one that’s petroleum-based. If you’re unable to find this type of spray, it’s okay to use a fluoropolymer spray.


Make sure to avoid silicone sprays and alcohol-based sprays. These types of spray will ruin the fabric of your canvas boat cover and will leave you with big, ugly patches.

How to Apply the Spray

To apply the spray, there are a few steps you need to follow:

  1. Find a well-ventilated space where you can start the spraying process.
  2. Make sure the cover is off the boat. That way you make sure the spray doesn’t affect any other part of the boat.
  3. Test the spray on any small, hidden part of the cover to make sure it doesn’t discolor the canvas.
  4. Spray a coat of spray on your canvas, then cover it with another coat perpendicular to it. This ensures ideal coverage and protection. 
  5. Leave the canvas cover to dry. Drying time will differ depending on the type and brand of spray you’re using. 
  6. After the waterproof spray dries, test the boat cover with some sprays of water and see how waterproof it is now.

How Effective It Is

Waterproof spray is an effective and easy way to waterproof a boat cover. It delivers excellent protection and doesn’t take much time and effort to be applied. 

However, depending on how much exposure to the elements your boat cover gets it will need to be reapplied in 6-12 months.

How Long It Will Last and When to Reapply

This option should last at least 3 full months. If the product you chose to use was a high-quality product, your boat cover might remain waterproof for around 6 months. 

You can test it every couple of months to check if it needs to be sprayed once more.

3. Use Wax

Another waterproofing method that was used way back by ancient Greeks and Egyptians while sailing is waxing.

It’s not as convenient as waterproof spraying, but it gets the job done!

What Type of Wax to Use

You can use fabric wax made from basic beeswax.


Just make sure you have enough wax bars for the whole canvas cover. Also, make sure you choose a colorless, odorless type.

How to Apply the Wax

In order to apply the wax, you need to do the following:

  1. Test the wax on a small part of the cover first to check for any drastic discoloration.
  2. Start rubbing the wax bar evenly back and forth on the canvas fabric. This will create heat, and therefore, friction, which will help the wax spread faster onto the fabric.
  3. Make sure you cover every spot on the canvas boat cover so the water wouldn’t slip on from any edge.
  4. The distribution of the wax on the boat cover must be as even as possible. So, don’t be afraid to help the wax get spread equally using your hands and fingers.
  5. The waxed fabric should be slowly and uniformly heated using a hair dryer. By allowing the wax to fully saturate the fibers, a uniform look and waterproof layer are produced.

How Effective It Is

Although this method takes longer to apply to the fabric than a waterproof spray, it stays there for longer as well. It provides you with unmatchable waterproofing quality at a low price.

How Long It Will Last and When to Reapply?

This method can provide optimal waterproofing for about a year. 

That said, if your boat usually endures harsh circumstances and you’re looking for a long-term solution for those raindrops slipping into your boat, waxing is the choice you should go for. 

Final Words

Waterproofing a canvas boat cover might sound like a lot of work, but it’s pretty easy and won’t cost you much. 

With the simple steps listed above, you’ll find yourself having a fully waterproofed canvas boat that can weather any storm. 

Whether you decide to wax the cover or spray it, you don’t need to worry because both options provide excellent results. 

Good luck!

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