Waterproofing a tent means cleaning the flysheet, refreshing the exterior DWR treatment, sealing interior seams, and renewing the PU coating when it flakes.
For the full breakdown, see our best 6 Person Tent Waterproof guide.
Rain beading up and rolling off your tent fly is the sign a factory DWR finish still works. When water soaks in instead, the tent needs reproofing. The process takes a few hours of work plus a full day of drying. Doing it right starts by figuring out which of the three waterproofing layers actually failed: the durable water repellent (DWR) on the outside, the seam sealing on the stitching lines, or the urethane (PU) coating bonded to the inside of the fly and floor.
Which Parts Of The Tent Need Waterproofing
REI identifies three separate waterproofing systems, and each needs a different treatment:
- DWR exterior — the chemical finish on the rainfly’s outside face that makes water bead and roll off.
- Sealed seams — the stitching lines where needle holes let water through; these get sealed on the underside or interior.
- PU coating — the moisture barrier bonded to the inside of the rainfly and the floor; it flakes away with age and needs renewal.
Test the tent first. Set it up and spray water on the fly. If it beads, the DWR is fine. If it soaks in, you need to reproof. Check inside for flaking white or yellowish powder on the fly and floor — that is PU breakdown.
How To Waterproof The Tent Fly, Step By Step
Clean the tent before applying anything. Jack Wolfskin’s guidance is to test the remaining waterproofing, clean thoroughly, choose a suitable product, apply, and dry. REI’s workflow adds the seam detail: set up in a dry, bright spot, inspect seams, remove loose seam tape, clean seam lines with rubbing alcohol, and apply seam sealer only where needed.
Use tent-specific cleaner with lukewarm water. Harsh detergents damage the fabric and strip remaining treatment, per the Camping and Caravanning Club.
Apply Seam Sealer First
Seams are the most common leak point. Apply seam sealer to the underside of the fly’s stitching lines or the inside of the tent body — never the exterior. Wipe the seam with rubbing alcohol, apply a thin, even coat (Gear Aid’s Seam Grip TF works this way), and let it dry before any other treatment.
Refresh The DWR On The Outside
Apply waterproofing spray to the outside of the rainfly only. Set the tent up, spray evenly across the fabric, wipe off excess after a couple of minutes, and let it dry completely. Different products need different conditions — check the bottle. Advnture notes Nikwax Tent & Gear SolarProof goes on a clean, wet tent, while Fabsil Gold Universal Protector requires a clean, dry one.