How to Waterproof Tents

Nothing compares to the great outdoors. At a time when our ability to socialize indoors is limited, more and more people are choosing to live the outdoor life, spending their time surrounded by the natural world, and camping is a big part of that.

There are lots of things to bear in mind when camping. For one, you don't want to be caught in a rainstorm overnight with a leaking tent. The good news is that you can waterproof even the best inflatable tent yourself using specialized equipment. 

Read on to see all the advice you will need for how to waterproof a tent by yourself.

Why You Need to Waterproof Your Tent

If you are purchasing a brand-new tent, you'll probably find that most of them are already waterproofed, and will come with a clear hydrostatic head rating. 

However, the more it is used, the less effective the water proofing agent will be. That's why you will need to waterproof a tent yourself for long-term use, or if you have purchased it second-hand. 

One way to see for yourself whether a tent needs waterproofing - without leaving it out in the rain overnight - is to use a water spray on the outside of the tent and see if the water beads on the surface.

If not - or if you notice anything seeping through - then follow our advice below for how to waterproof your tent.

Just like skin, fabric is sensitive to ultraviolet light and will be prone to sun damage. In particular, exposure to the sun over a long enough period of time might compromise your fly sheet, which is the tent's line of defense against heavy rain. A DWR (durable water repellent) coating will provide the best relief to a sun damaged fly sheet.

Over time, you also risk damage to your tent seams. Although fully sealed at first, over time the seams will become the weakest points of your tent and may even require a special seam sealer.

What Happens if Your Tent is Not Waterproof

Even when you're not in your tent, you don't want to leave any possessions in an environment where they might become damp or water damaged. Camping gear is expensive, so you'll want to keep it safe and dry.

You can also catch hypothermia when sleeping in wet clothes, or using a particularly damp sleeping bag. A waterproof tent is a necessity if you want to stay safe and healthy during your camping trip.

Identify the Problem

It can be very expensive to treat your entire tent with water repellent, and often it isn't necessary to do so. Depending on the last time you waterproofed your tent, it might be the case that only one part requires reinforcement.

That's why it is critical to identify the problem. Try pitching your tent in the backyard in the rain, or even using a garden hose to see if, and where, your tent is letting in water. Usually, the problem is likely to be the seams.

Different parts of the tent will require different waterproofing treatment - for example, the main fabric of your tent body can be treated with a DWR waterproof spray, but leaky seams will require specialized seam sealant.

Check the Tent Before You Go

Below, we have written a handy checklist of things you should remember when examining your tent for waterproofing weak spots, which could save your belongings from a soaking if you end up camping in the rain!.

Are the ties tight?

Before you go buying expensive waterproofing treatments, make sure you have pitched your tent correctly! Your tent will perform best with secure ties and tight guy lines, and this is one of the most common ways for water to enter your tent.

Most tents will come with a separable rain fly - this is basically the floor-less waterproof tarp, or outer layer of your tent fabric. If this has not been secured correctly, it will not provide effective protection against rain and moisture.

Are the seams sealed?

If your tent is letting in water, there's a good chance this is happening through the seams, since these are the parts which become weakest over time. 

Every time you use your tent, the seams are being stretched further out of shape. This is what they are designed for - but it also means they are less durable than other parts of the tent. To fully waterproof your tent, you'll have to seal the seams.

If your garden hose test has shown you that water is leaking through your tent seams, you should clean the seams with rubbing alcohol and then apply seam sealant or seam tape to improve the water protection on your tent's weak spots.

Is the groundcloth secure?

Moisture can also enter through the tent floor. It might be quite easy to miss this, since it won't be immediately obvious from the garden hose test. It can be a nightmare if you need to set your tent up on wet ground, or if you are pitched on a slope and severe rainfall means water is getting under your tent.

Your rain fly usually won't have a bottom, so the tent floors will feed directly to the ground outside. That's why it is so important to keep it watertight. There are a few good ways to do this:

  • A tent floor footprint (also known as a groundcloth) is an extra piece of tent waterproofing gear you can buy, which provides an extra layer of protection between the tent floor and the wet, grassy ground.
  • Regular tent waterproofing spray can also be used to reinforce the exterior bottom of your tent.
Waterproof Tent Checklist

Waterproofing Treatments

Depending on which part of your tent needs treatment, there are different treatments available you can use for waterproofing your tent. Specialized sealant exists for tent seams and other products are normally used for the tent fabric, so make sure you have identified the problem first.

Seam sealer must be applied carefully, and only after cleaning your seams with rubbing alcohol and a cloth. Usually, the product will come with instructions for use since different brands suggest different applications methods. It is best to check the packaging directly.

Alternatively, you can buy a water repellent canvas tent coating which goes up around your tent. This is easier than waterproofing your tent with chemicals, but it requires you to carry more heavy gear on your camping trip.

Waterproofing Spray

To protect the main fabric of your tent, there are many good brands of DWR treatment you can buy. These work as a chemical sealant which makes the outer fabric more water repellent.

The most common form of treatment you can find is waterproof spray. There are many excellent options out there, so choose one that fits your tent manufacturer's instructions. Apply this liberally to the tent fabric, and then wipe off any excess with a damp cloth. Make sure your tent and gear are completely dry before packing them up.


Below are a couple of commonly asked questions about tent waterproofing.

1. What is the best waterproofing for tents?

Since the tent seams become weakest over time, chemical seam sealer is the most useful product for waterproofing a tent. Before you seal the seams, you'll need to clean and dry them carefully and then apply your sealant by following the relevant instructions.

A great waterproofing agent should protect against the causes of waterproofing, as well as provide effective moisture resistance to your tent's fabric. 

Some brands of tent sealant also have ultraviolet light blocker to prevent the worst effects of long-term sun damage on your tent's exterior, such as Nikwax Tent and Gear Solarproof.

Sun damage is one of the leading causes of waterproofing breakdown, so protecting against this minimizes the number of times you'll need to re-waterproof.

2. Do you need to waterproof tents?

In a word - yes. Lots of tents will already come waterproofed, but this isn't a guarantee. Additionally, damage to the seam and rain fly are likely over time, so it is always good to know how to waterproof a tent, as it will come in handy sooner or later.

If you are put off by the effort, an external canvas covering can be an easier option. It is simpler to pitch a cover over your tent than to go to the effort of applying chemical fabric and seam sealant. But, waterproofing your tent properly provides longer lasting and more robust protection against bad weather.

For one, an extra covering is just additional gear that you'll have to carry around with you. This isn't a major problem if you are simply camping with the family in your backyard, but it can be unwanted extra weight for a long nature hike.

Another benefit to waterproofing your rain fly instead of using a canvas covering, is that pitching your tent takes less time. 

Overall, waterproofing the rain fly with spray chemicals takes time, but it is something which will make your life easier in the long run if you are setting up your tent regularly.

3. How do you make a tent waterproof?

Depending on the type of material used, there might be some additional steps before you are ready to apply your chemical water repellent coating.

A new polyester tent should be ready to go straight from the box. On the other hand, if you have a new polycotton tent, you should remember to weather it before use - even if you bought it first-hand. Cotton is naturally waterproof, so only needs a thin layer of chemical water repellent - if at all. However, the fabric still needs to be "broken in" - so to speak.

To weather a polycotton tent, simply set it up in the yard on a dry day and soak it with the garden hose, then let it dry by itself. This will reinforce the DWR coating on the rain fly.

If you are applying seam sealant, you'll need to give your tent a good clean first using rubbing alcohol and a dry cloth.

If you are using a treatment chemical spray on your rain fly, it should be enough to wet the fly with a hose before applying your DWR coating. Just remember to clean off the excess afterwards with a damp cloth.

4. Does waterproof spray work on tents?

Chemical DWR spray is the best way to waterproof a tent. This works best when applied to your rain fly - but won't do as well on the seams, which have their own specialized waterproofing agents.

Your tent might not come with a rain fly - that's alright, you can also buy spray products designed for single-layer tents. Make sure you purchase the right kind of spray for your tent by checking what kind of tent you have, and whether it comes with a rain fly.

An alternative to chemical sealant is to buy an external tarp covering. This might be the easiest solution for backyard camping, but if you plan on hiking, then the less heavy gear you have to carry, the better.

5. Can you waterproof a nylon tent? 

The short answer is yes - you can!

Compared to other fabrics which are commonly used to make tents, nylon isn't particularly waterproof.

This means that waterproofing a nylon tent is an absolute necessity. Luckily, the manufacturer should already have taken care of this by applying a waterproofing agent such as a polyurethane coating to the fly sheet before selling the tent, but after significant usage it can and should be topped up.

To waterproof a nylon tent, simply follow the instructions above for waterproofing any DWR fly sheet.

Make sure the sheet is clean and wet (ideally using a hose) and then apply the waterproofing spray, cleaning off the excess with a damp cloth. You'll need to seal the seams as well using a specialized seam sealer, which can be bought from any store which sells tents and similar gear.

6. How long does tent waterproofing last?

The answer to this question totally depends on how much use you get out of your tent. You can always wait until it starts leaking, but you don't want to get caught out in the rain with a tent which leaks water!

Your tent's HH (Hydrostatic Head) rating should give a good indicator of how long it can go before it needs re-proofing. The higher this number, the more resistant your tent will be to the effects of long-term use.

Generally speaking, tents should last a good couple of years without needing re-sealing - if you look after them properly. The first sign that a tent might need re-proofing will be the seams, since they stretch the most. Seam sealer can help to prolong the water resistance of your tent. 

7. Do you waterproof the inside or outside of a tent? 

This might sound at first like a bit of a silly question. Rain water enters from outside - so surely outside should be the only part of the tent you focus on, right?

Wrong. While it is necessary to reinforce the DWR coating on the outside of your tent (usually the rain fly), it is also important to take care of the urethane coating on the underside of the material.

A good way to know if your urethane coating needs reinforcing is to check whether the inside of your tent is flaking off. If this is the case, it is a good idea to use specialized tent sealant for whatever kind of fabric your tent is made of.

Your sealant should come with specific instructions for how to do this best.

8. What material are waterproof tents made of?

Many different fabrics are used to make tents.

There's nylon, which is thin and not very stretchy, so is not particularly waterproof.

Polyester is slightly heavier and more expensive, but is a better fabric for making tents. Like nylon, it isn't very waterproof - so tents made using polyester are usually coated with a polyurethane coating by the manufacturer when they are made. This coating is what makes the tent waterproof.

A better type of fabric for naturally waterproof tents is polycotton or canvas. Cotton naturally swells when it is wet - this closes up tiny gaps in the fabric when it makes contact with water, and acts as a sort of natural tent waterproofing agent. This is why a lot of individually sold fly sheets are made of canvas.

If your tent is made of polycotton or canvas, you may want to weather it before using it. Check above to see our advice on the best way to weather your tent.

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