A camping tent is designed to keep you warm and dry when the weather doesn’t want to cooperate.
However, anyone who has spent time outside and has experienced the steady drip, drip, drip of water in a tent might be wondering: Are tents waterproof?
Most tents are designed to be waterproof, though even the best of shelters can fail in a storm if they’re not pitched properly. Additionally, many tents need to be seam-sealed before their first use and all tents need to be re-waterproofed multiple times a year.
We know how important it is to feel confident in your tent while camping. To ensure that you have all the information you need to stay dry on your next rainy outdoor adventure, here’s everything you need to know about waterproofing a tent.
Are Tents Waterproof?
As we’ve already mentioned, most tents are, indeed, designed to be waterproof. Whether they live up to that expectation is an entirely different story.
Waterproofing in a tent comes down to 4 factors:
- Fabric quality in the rainfly and floor
- Waterproof treatments on the rainfly and floor
- Construction of the tent
- How you pitch the tent
If you’re wondering whether a tent is truly waterproof, you’ll need to do a bit of sleuthing to find the answer.
How to Find Out Whether or Not a Tent is Truly Waterproof
The vast majority of tents are made from either ripstop nylon, ripstop polyester, or canvas fabrics.
Each of these fabrics is naturally water-resistant, as they have tightly woven fibers that are too small for most water droplets to pass through.
In fact, even ultralight tents made from extremely thin ripstop nylon can be waterproof, though they are more prone to tearing in the wind.
The water-resistant properties of a tent come more from the quality of the fabrics used than the thickness of the fabrics themselves.
So, to determine whether a tent is actually waterproof, check to see if it has a nylon, polyester, or canvas canopy and floor. If so, it meets our first waterproofing requirement.
Once you’ve determined whether a tent is made from naturally water-resistant fabrics, it’s time to dig a little deeper and learn more about the different waterproofing treatments that it has.
There are 3 types of waterproof treatments:
- DWR (durable water repellent)
- Urethane coating
- Seam taping/seam sealing
How Durable Water Repellent (DWR) Works
The first treatment, DWR, is a chemical that’s sprayed onto the majority of tents, rain jackets, and other outdoor fabrics.
When applied properly, this chemical helps water bead off the surface of the fabric, preventing it from soaking through.
DWR does wear off over time, so it needs to be reapplied regularly—usually after every 3-6 months of use.
Reapplying DWR is fairly easy, as it’s usually available in a spray bottle that can be applied to the outside of a tent rainfly in just a few minutes and then left to dry.
Tent Urethane Coatings
In addition to a DWR coating, which is applied to the outside of a tent rainfly, most truly waterproof tents have a “urethane coating.” You can often see evidence of this urethane (or polyurethane) coating in the white flakes that peel off the inside of your rainfly or floor after years of use.
This urethane coating helps seal off the inside of your tent fabric so that water can’t soak through. Indeed, it serves as a second layer of defense if your DWR fails.
Many companies try to communicate the quality of their tents’ urethane coating by using a PU
rating or HH (hydrostatic head) rating. These ratings are expressed in terms of mmH2O, with higher ratings, like 10,000mm, representing how much water pressure the fabric can withstand without soaking through.
Contrary to popular belief, the PU rating or HH rating of a tent doesn’t tell you how much urethane coating a tent has. Nor does it tell you how waterproof a tent actually is.
In fact, adding more than about 2-3 coats of urethane to the inside of a tent just to achieve a higher PU often increases the weight and bulk of the fabric without providing any real waterproofing benefits.
Even a tarp with a 600mm PU rating can be fully waterproof if it’s made from quality materials and is pitched properly.
Tent Seam Taping/Seam Sealing
The final layer of waterproof treatment that tents often have is called seam taping.
While the fabric of a tent can be fully waterproof, the process of sewing fabrics together creates tiny holes around the seam.
These small holes become a weak area in the tent and can cause water to seep through and drip onto your head. Needless to say, this is not a fun experience.
To counter this issue, many companies seal off the seams on their waterproof fabrics. When this is done at a factory, most manufacturers use seam tape, which is a very thin layer of polyurethane film.
This tape is placed over all of the seams on a tent to stop water from entering through the needle holes in the fabric.
Many tents come fully seam taped, which means they’re normally waterproof right out of the package.
Seam tape is most effective on fabrics thicker than 68D, but it’s less effective on thinner fabrics, as it tends to degrade much more quickly.
Some tents, especially budget and lightweight models, will require that you manually seal the seams of the shelter at home before you use it for the first time.
This process is somewhat time-consuming, but it’s not particularly difficult. You’ll just need a free afternoon, a tube of Seam Grip, and some good music to listen to as you brush a thin layer of polyurethane over the seams of your tent.
In fact, even if your tent came fully seam taped from the factory, you will, at some point, need to reseal it. Depending on how frequently you use your tent, you may need to do this every 6-12 months to ensure that your tent stays fully waterproof.
The third consideration when determining whether a tent is actually waterproof is to look at the tent construction. Even a tent made from top-of-the-line waterproof materials will fail to keep you dry in the rain if it’s not built for a storm.
If you’re in the market for a new tent, it’s worth taking the time to thoroughly critique the design of the shelter to determine whether it will truly protect you from the rain during a storm. Here are a few things to keep in mind:
Tents come in many shapes and sizes. When looking for a model that will keep you dry, you’ll want one that has sloping sides and an angled roof.
More often than not, cabin-style tents, which have flat roofs, will collect water on the top of the rainfly during a storm. Over time, the rainfly will give way to all this pressure and will allow water to drip into your living area. Thus, dome, geodesic, A-frame, pyramid, and tunnel tents tend to be more effective in the rain.
Your tent’s rainfly is your primary line of defense against the rain. However, many tents—particularly those designed for car camping—come with rain flies that protect only the upper portion of the tent.
This is beneficial in nice weather situations, as it allows air to flow through the tent for added ventilation. On stormy days, however, water tends to leak through the windows and doors of these tents.
Moral of the story? If you camp somewhere with minimal rain, a partial-coverage rainfly might be just fine. For backcountry use or for camping trips in rainy locales, a truly waterproof tent will have a full-coverage rainfly to keep you dry.
These days, most tents come with a “bathtub-style” floor, which is just a fancy way of saying that the waterproof floor fabric of the tent extends upward about 2-10” (5-25cm) off the ground.
Bathtub-style floors are essential for waterproofing because they prevent the inside of your tent from getting wet when you’re camping on soggy ground. Water also tends to run on the surface of the ground in heavy rainstorms, which can leak into your tent.
Therefore, these floors will prevent water from entering your tent, for a drier camping experience.
How to Waterproof a Tent
If you recently arrived home from a camping trip, you may have returned home with a wet tent. If so, here is an article you might find quite handy >> How To Care For Your Tent (Complete Guide)
Tent Pitching Practices
Finally, it’s important to note that the best tent in the world will not keep you dry if it isn’t pitched properly!
Small things, like ensuring that your tent’s rainfly is properly tightened down using the guylines, can make a big difference during a storm. A slack rainfly is more likely to collect water, which can seep into even the most waterproof of tents over time.
So, take the time to learn how to pitch your tent properly before your first trip. Then, be sure to set it up with care each time.
Most tents are designed to be waterproof, thanks to their waterproof fabrics and treatments. Whether your shelter will actually protect you in the rain depends on the specifics of its construction and how well you pitch the tent when you arrive at camp for the night.
Gaby is a professional outdoor educator, guide, and wilderness medicine instructor. She holds a master's degree in outdoor education and spends most of her time hanging out with penguins and polar bears in the polar region. When she's not outdoors, you can find her traveling, reading Nietzsche, and drinking copious double espressos.