There’s nothing worse than hunkering down for the night in your cozy little tent, listening to the rain beat down outside, and feeling that dreaded drop of water hit your nose…
“But, surely this tent is waterproof?” You might ask. And many people would assume the same. But the answer isn’t as simple as it seems. For not all tents are actually waterproof.
Although some tents are indeed waterproof, many are simply water-resistant, and there’s a whole range of ways for tents to keep out water – and some backpacking tents are definitely better than others.
Here, we’ll go through what actually makes a tent waterproof as well as some techniques for waterproofing your own tent at home.
So how can you tell if a tent is waterproof in the first place? Well, waterproof tents are made of fabric that keeps water out entirely, although this rarely lasts forever. The degree to which waterproof tents keep out water also varies but, luckily, there’s a way to compare the waterproofing of different fabrics.
The Hydrostatic Head (HH) of a tent tells us how well it can keep out water. It measures in millimeters how much water the fabric can resist when a column of water is held above it. For example, if a material has a HH of 1000 (1000 HH), it can withstand the pressure of holding a 1000mm water column above it – anything above that and the water will start to seep through. So, the larger the HH rating, the larger the water column it can resist and the more waterproof the fabric is.
When you’re looking at tents, the lowest waterproof rating you’ll typically find is 1000 HH – anything lower than this it is not considered waterproof. Although 1000HH is enough to keep you dry in light showers, if you’ll be out in serious rain, you’ll find that this isn’t enough. On the other hand, tents with a 3000 HH rating are made for torrential rain. Although they’ll cost more, if you’ll be out camping in extreme weather, this is the way to go. Most waterproof tents, however, have a rating of 2000HH, which is perfect for a three-season summer tent.
Some fabrics, such as laminates, can achieve a high HH rating in their own right – their pores don’t let water pass through. However, most fabrics used for tents are treated with some kind of coating to increase their hydrostatic rating.
The most commons ones you’ll see are polyurethane (PU) and silicon coatings, and these essentially provide a thin layer of waterproof film to your tent. These coatings can really ramp up your HH rating, but they will add a bit of weight to your tent overall.
You’ll also see tents advertised as having a durable water repellent (DWR) finish. This makes fabrics hydrophobic – which means they don’t like water – so they repel water instead of absorbing it. You’ve probably seen this in action if you’ve ever worn a waterproof jacket – the beading up of water droplets on the outside is caused by the hydrophobic fabric repelling the water. This mechanism of action means that DWR finishes work wonders when applied to the outside of your tent’s rainfly, and it’s also way lighter than PU and silicone coatings.
Although a high HH rating means that your tent, in theory, will be able to stand up to the elements, this is not always the case. In reality, poorly constructed tents with a high HH rating are anything but waterproof. When you’re hunting for a tent that will stand up to bad weather, make sure you keep an eye on the seams, the zips, and the groundsheet, as these are all potential sources of leaks.
Ideally, seams should be double-stitched and the holes need to be sealed too, and they can even be inverted to prevent leakages. Similarly, the holes on zippers can let water through, so you want to make sure that they’re covered. Finally, groundsheets often have their own HH rating, so make sure that’s high enough, and you want it to be thick enough to stand the test of time too. Integrated groundsheets simplify setting up your tent and don’t leave any gaps, and there are now so-called bathtub groundsheets that have raised edges to minimize water entry too.
So, a tent that is actually waterproof will have a high HH rating, will most likely be treated with some form of coating, and will have been cleverly constructed to keep water out.
Maybe you’ve finally found a tent that you love but, sadly, it isn’t as waterproof as you were hoping for. Or maybe your favorite camping tent that you’ve had for years has developed a few leaks. Is it game over? Not at all! There are heaps of tricks you can use to help your tent stand up to bad weather.
Not all tents come with sealed seams, and it would be a shame not to pick up the tent of your dreams because you’re worried about seam leaks. Plus, even sealed seams can eventually let water in as the sealant wears away or the threads come loose. So why not seal your own seams?
Sealing seams is easy – just follow these simple steps:
One thing to bear in mind during this process is that materials with different coatings require different sealants – so make sure you use the right one. Coleman makes a great budget sealant for PU-coated materials and we love the GEAR AID sealant for silicone-coated tents.
When you notice that your rainfly and groundsheet are starting to flake, you need to get ready to replenish the coating.
Again, the method is nice and simple:
As before, you typically need to make sure that your coating matches the original – so use a PU spray (like this one) for PU-treated tents and a silicon spray (like this one) for silicon-treated tents, although some sprays (like this one) can be used for both.
To refresh the DWR coating on your rain fly:
For a breathable yet effective DWR coating, check out the Nikwax Direct Spray.
But how often should you be doing this? Well, that depends. If you’ve just purchased a high-quality tent, then you should be safe for a couple of years. However, if you’ve gone for a budget option, you may run into trouble sooner. And bear in mind that the more frequently you use your tent, the more regularly you’ll need to waterproof.
Some people prefer to simply wait until there’s an issue with their tent before taking any kind of waterproofing action. If you’ll be going on very casual camping trips this might not be a bad way to go, but if you’re planning some extensive camping trips, you might prefer to pre-empt any potential issues for added peace of mind.
Inspecting your tent regularly, and particularly before big trips, is the best way to avoid problems. Fraying seams are easy to spot, so we don’t go into details there. Leaky seams, however, are a little bit trickier. One way to check your seams is to assemble your tent and have someone pour water over the seams, while you wait underneath and keep your eyes open for leaks. This method might not be foolproof, but it certainly will identify any large holes.
Similarly, a good way to check the DWR finish is to pour water on the outside of your tent – if you notice the little beads of water are no longer forming on the surface, then it’s time for a new coating.
You also need to check for material flaking away from the inside of your rainfly and/or the groundsheet. If you spot this, then you need to replenish your PU or silicone coating.
If you have the time and space for it, you could even take your tent for a test run somewhere close to home before heading out on any big adventures.
So, overall, there is no set rule on waterproofing. If you’re willing to take the risk, the most cost-efficient way is to simply wait until you encounter an issue. Inspecting your tent every now and then can help you to prevent most potential issues, but if you prefer to play it super safe, then we’d recommend waterproofing every couple of years, or sooner if you’re planning a big trip.
So, there you have it, some simple ways to waterproof your tent. But waterproofing doesn’t always have to involve fancy seals and sprays. Fortunately, one of the most effective ways to waterproof your tent is also one of the simplest.
No matter how many precautions you take, there’s still a chance you’ll be unlucky and end up with a leaky tent. But what if you could add a whole extra layer of protection to your tent? Well, you can. Pitching a tarpaulin above your tent reduces the amount of water coming into contact with your tent in the first place, so you’re less likely to get water entering through any weak points.
There are heaps of heavy-duty tarpaulins on the market, but we’d recommend going for a kit that comes poles as well as ropes. The general steps for pitching a tarp over a tent are as follows:
So, are tents waterproof? In short, not entirely. However, they can do a pretty good job of keeping water out if they’re made in the right way. The best tents will have a combination of different water repellent coatings, and they’ll also have a solid construction that doesn’t leave any weak spots. When you’re shopping around, keep your eye on the HH rating, the combination of coatings used, and check that the seams are sealed and the zippers are covered. If possible, go for a bathtub-style groundsheet, as these are the best way to stop water from entering at ground-level.
But even the best tents will eventually start to leak. However, as we’ve seen, this doesn’t mean it’s the end of the line for your favorite tent. Most leaks can be overcome with some simple maintenance, and inspecting your tent on a regular basis is the best way to make sure you don’t get caught out on a rainy camping trip. If you don’t have time to waterproof your tent before you head out, or you just want some added security, then you can always take a tarp with you for some added protection.
Now you know what makes a tent waterproof, what to keep an eye on when you’re purchasing a tent, and how to waterproof your tent at home – say goodbye to soggy camping trips!
Roger is a little obsessed with travel. He has been to over 40 countries, broken 3 suitcases and owned over 10 backpacks in 12 months. What he doesn't know about travel, ain't worth knowing!