How to Waterproof a Tent

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How to Waterproof a Tent

Want to Learn How to Waterproof a Tent?

You’re in the right place! In this guide, we will be covering the following:

    • Why re-waterproofing your tent is necessary.
    • How to reapply the waterproof coatings
    • How to seal your tents seams

After a certain number of outings, any tent can start to lose a little of its capacity to fend off the wet stuff. The good news, however, is that with just a little bit of effort you can restore your tent’s waterproofing capacity to as good as new.

Below, we’ll explain how it’s done with a short guide to how to waterproof a tent.

Reproof a Tent in Three Easy Steps

The main cause of leaks in any tent is the deterioration of manufacturer treatments to the tent’s seams, the DWR coating, and/or the waterproof polyurethane or silicone coating.

Before setting out to restore your tent’s waterproofing capacity by renewing any of the above treatments, it’s best to clean the tent with cold water, mild soap, and a soft sponge. This will make sure there are no contaminants or corrosives (muck, sand, sap, animal scat, suncream, etc.) that might hinder the effectiveness of reproofing.

After leaving the tent to dry (ideally on a line), then you’re ready to get down to the business of reproofing.

Reapply the Polyurethane or Silicone Coating 

Polyurethane (PU) coatings used in tent floors and flysheets are prone to chemical degradation, meaning that the PU coating simply dissolves over time. This is usually discovered when the coating starts flaking on the tent’s interior.

While silicone coatings are far more durable and reproofing is rarely necessary, if you have subjected the tent to a fair amount of rough treatment you may begin to notice smaller leaks that can be eliminated by retreating the fly and flooring.

1. Collect your kit: a rag, rubbing alcohol/surgical spirit, and the correct type of tent sealant (a silicone sealant for silicone-treated fabric and a PU sealant for polyurethane-coated fabrics).

2. Lay your tent’s rainfly and floor out on a flat surface and remove the flaking coating by scrubbing it off gently with the rubbing alcohol and rag (use an abrasive sponge if the rag isn’t working).

3. Apply the new sealant as directed in the product instructions (check out our guide to the best tent waterproofing products.

4. Wash your hands thoroughly—all tents use flame-retardant chemicals that have been linked to several damaging health effects.

5. Leave the new coating to dry and “cure” for a minimum of 24 hours before stowing your tent back in its stuff sack.

Renew Your Tent’s DWR Coating

A tent’s DWR (Durable Water Repellent) coating is what allows it to shed water upon impact and provides the first line of defense against precipitation. This coating is less durable than waterproof PU or silicone coatings and usually requires renewal after every 10-15 outings. Thankfully, however, the process is very simple.

If you notice that rainwater is no longer beading up on your rainfly:

1. Collect your kit: a rag or towel, a bucket of tepid water, and a bottle of waterproofing spray (like Gear Aid Revivex or Nikwax Tent and Gear SolarProof).

2. Pitch your tent and spray down the fly with water.

3. Spray the waterproof treatment evenly over the rainfly’s exterior.

4. Leave the tent to dry thoroughly before returning it to its stuff sack.

Reseal Your Tent’s Seams

The seams in a tent are its greatest points of weakness, mainly due to the fact that they have hundreds of tiny needle holes created in the process of stitching two pieces of fabric together. If you discover your tent has a leak, therefore, this is the first place to check.

While most tents have sealed seams, the tape or treatment used to create the “seal” requires occasional renewal over the tent’s lifespan. Here’s how it’s done:

1. Collect your kit: a rag, rubbing alcohol/surgical spirit, seam sealant (silicone sealant for silicone-treated fabric and PU sealant for polyurethane-coated fabrics).

2. Make sure your tent is completely dry and the seams free of dirt.

3. Pitch your rainfly inside out or lay it out on a flat surface with the underside exposed.

4. Gently remove any flaking tape, leaving intact tape in place.

5. Wipe down each seam with your rag and rubbing alcohol.

6. Apply the new seam sealant to the seams.

7. Allow the sealant to dry completely before packing your tent away (usually 10-12 hours).

Kieran James Cunningham is a climber, mountaineer, and author who divides his time between the Italian Alps, the US, and his native Scotland.

He has climbed a handful of 6000ers in the Himalayas, 4000ers in the Alps, 14ers in the US, and loves nothing more than a good long-distance wander in the wilderness. He climbs when he should be writing, writes when he should be sleeping, has fun always.

Kieran has taught mountaineering, ice climbing, and single-pitch and multi-pitch rock climbing in a variety of contexts over the years and has led trekking and mountaineering expeditions in the Alps, Rockies, and UK. He is currently working towards qualifying as a Mountaineering and Climbing Instructor and International Mountain Leader.

Kieran’s book Climbing the Walls—an exploration of the mental health benefits of climbing, mountaineering, and the great outdoors—is scheduled for release by Simon & Schuster in April 2021.

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