how to waterproof a canopy beaded water on material surface

How to Waterproof a Canopy and Stop Those Leaks

If you’ve noticed that your canopy or gazebo is leaking water, or that rain is not beading off the surface effectively, then it might be time to perform some canopy first aid. Learning how to waterproof a canopy is fairly easy, but it’s important to understand how you are limited by your starting material.

What waterproofing outcome to expect

To shape your expectations of the final result, it’s useful to know whether your canopy was originally designed to be waterproof, water resistant, or for dry use only. Not all canopies/gazebos are designed for wet weather, so do your research on the best pop up canopy for your situation before you buy. If you have already purchased one check the information provided from the manufacturer. If this doesn’t give you the answer, the section below will help you understand some material generalisations, and may give you some clues to your canopy’s ability to keep out water.

Canopy fabric and waterproofing properties

Polyester is a common fabric used in pop up canopies, gazebos and tents. Polyester itself is not technically waterproof, but can be considered resistant to water if it’s thick enough. Sometimes manufacturers apply a waterproof coating on top of the polyester, which are generally polyurethane or silicon-based. Unfortunately if you have a pure polyester canopy with no waterproof coating, you’re not going to be able to achieve a truly waterproof product. However you can:

  • Apply a water-repelling spray to reduce how much water soaks in to the surface
  • use a seam sealant to improve the performance of the seams
  • or fix an obvious hole.

Some heavy duty/commercial grade canopy tops are actually made of polyurethane material which makes for a very waterproof product, albeit a heavy one. Any waterproof material or coating can wear and crack over time with frequent folding and unpacking, which degrades how well it will keep out water. If your pop up canopy fabric is inherently waterproof, or is coated with waterproof material, you have the waterproofing option (in addition to the polyester options above) to refresh the coating for full ‘waterproofness’.

The other less common canopy/gazebo fabric I’ll mention here is canvas, which today is typically a cotton-based product. Canvas is naturally water-resistant, as long as you wet the surface with water before using it for the first time. For those with canvas, you need to be careful applying anything to the surface as you might ruin its natural water-resistant properties. Applying a light spray treatment may be beneficial to improve the beading of water off the surface.

Waterproofing Options

It’s important to understand what water egress issues you are having or trying to protect against. The next time you get inundated with rain while under your canopy, take note of where there are any leaks. Alternatively set your canopy up in the garden, and have someone spray water onto the roof while you watch for leaks underneath.

How to patch a tear or small hole in your canopy

  1. Clean the area with methylated spirits or other rubbing alcohol and a cloth/rag
  2. Cut some tent repair tape to cover the tear allowing for a decent buffer around it
  3. Press the patch over the hole whilst resting on an even surface
  4. Leave the patch to cement onto the fabric for the recommended time (from repair tape manufacturer) before stashing back in your tent bag
  5. Consider patching both inside and outside of the tear if it’s an area under high tension

How to waterproof a canopy fabric using a water repelling spray/treatment

Always follow the directions on the product you are using, but here is a general outline that works for most:

  1. Setup canopy or gazebo so that the fabric is taught but low enough to reach (use lowest height setting on a pop up canopy)
  2. Shake can well
  3. Test spray on a small surface to test colorfastness. If damage or color runs then try a different product
  4. Hold the waterproofing product about 15-20cm away from the fabric surface
  5. Spray at a comfortable pace, evenly over the whole fabric. Ensure you keep track of where you have sprayed to avoid missing any areas.
  6. Allow to dry completely, and then spray a second coat.
  7. Once dry again, drip some water over some of the fabric and check that it beads off. If you find it is soaking or not running off well apply a third coat.

How to restore the waterproof coating on a canopy fabric

If the polyurethane or silicon based coating is degrading in parts of your canopy, you can refresh the coating in these areas with an appropriate sealant. Ensure you have purchased the right type of sealant for your canopy material.

  1. Find the degraded patch of canopy material, and set it out on a flat surface.
  2. Use a scrubbing sponge (slightly rough) and rubbing alcohol (e.g. methylated spirits) to gently remove the flaking parts of the coating
  3. Apply sealant evenly and as directed by the manufacturer
  4. Leave to dry for the recommended time before use or storage

How to fix a leaking seam (join) on your canopy

  1. Lay out your canopy fabric on a well-lit and flat surface so you can scrutinize the underside
  2. Check to see if any current seam sealant is flaking off (be careful not to lift intact sealant), and remove this with a cloth and rubbing alcohol.
  3. Apply a seam sealant (ensure it’s the correct type for your material) to any locations that need refreshing. If the seams have never had any sealant on them previously, apply some to any known leak spots. If you can’t pin point the source of the leak, or want to increase your canopy’s future durability, then you could try applying sealant to the whole seam.

Additional Resources

This video from REI provides an overview of the things I’ve discussed. It’s focused on ‘tents’ however the concepts carry across to pop up canopies.

FAQ

Does waterproof spray really work?

If you are looking for a solution to make your canopy waterproof, then applying a water-repelling spray will not solve your issue. These sprays help water fall off the surface of your fabric by reducing the surface water tension. So it would be more accurate to say that it improves the water-resistance of the fabric, such that water doesn’t have as much opportunity to hang around and soak through. If you want true waterproofing, you need to apply a polyurethane or silicone based sealant. The best option is to choose a canopy that is designed to be waterproof, rather than trying to seal all the surfaces yourself.

How do you keep water from pooling on the canopy?

There is nothing worse then being stuck under a canopy in the rain, and having to constantly poke the ceiling to stop the water pooling. If you are looking to purchase a non-pooling canopy that has extra supporting arms between the corner uprights (most cathedral style canopies only have the four uprights at the corners to support the ceiling). Some pop ups also have tiny drain holes in the edge of the canopy to allow water to run off the canopy. If you already have your canopy, try this simple trick: grab a pool noodle and cut it down its length so that you have one flat side, and one rounded. Cut it to a length that will fit snugly between the underside of the edge to the peak of the canopy, and install in the middle of each of the four sides. This will keep the tension up on the areas where the canopy top tends to sag and collects water as they are furthest from the supported corners. Using a pool noodle is a great for taking on trips as the are light, although they can take up extra room.

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