Why Tents Start Leaking

Tent waterproofing fails for two different reasons: the seam sealer peels or cracks (water enters through needle holes in the stitching), and the DWR (Durable Water Repellency) coating on the fabric wears off (the outer fabric wets out and stops beading water, making it feel damp inside even without actual leakage). Both are fixable and are separate treatments.

Job 1: Reseal the Seams

  1. 1

    Identify failing seams

    Set up the tent. Check the inside of the fly for peeling, cracked or flaking seam tape or sealer — most visible at the ridge seams and corners. This is where water enters most commonly.

  2. 2

    Remove old failing sealer

    Gently peel or scrape off any peeling seam tape. Use rubbing alcohol on a cloth to clean the seam area thoroughly — new sealer will not adhere well to dirty or contaminated surfaces.

  3. 3

    Apply new seam sealer

    Use a seam sealer appropriate for your tent material. Silicone-coated tents: use a silicone-based sealer (Gear Aid Sil-Net). Polyurethane-coated tents (most budget tents): use a polyurethane sealer (Gear Aid Seam Grip WP). Apply along all stitched seams on the inside of the fly using a small brush. Work into the needle holes. Allow to cure completely (24 hours minimum) in a well-ventilated area before packing the tent.

Job 2: Restore DWR Coating on the Fly

  1. 4

    Clean the fly first

    Wash the tent fly with a technical fabric cleaner (Nikwax Tech Wash, Gear Aid ReviveX Wash-In). This removes dirt and oils that inhibit DWR performance. Do not use regular detergent — it strips DWR and leaves residue.

  2. 5

    Apply DWR treatment

    Spray-on (easiest): Spray Nikwax TX Direct Spray-On or Gear Aid ReviveX Spray-On Water Repellent onto the damp fly. Spread evenly. Let dry naturally or tumble dry on low (heat helps activate DWR). Wash-in: Add the DWR wash-in product to the washing machine with the fly. The DWR bonds to the fabric fibres during the wash cycle.

The bathtub testAfter treatment, set up the fly and pour water over it. Water should bead and run off immediately (good DWR) rather than soaking into the surface (wet-out = poor DWR). Re-treat the fly every 2–3 camping seasons or whenever you notice the fabric wetting out rather than beading.

Frequently Asked Questions

Seam leaking (water dripping from specific points, usually above sleeping area): reseal the seams. Water seeming to come through the fabric but not at a specific point: DWR failure — water is soaking into the fabric and creating humidity inside rather than beading and running off. Both issues can occur together. A tent that is several years old and used regularly likely needs both treatments.
Standard Scotchgard works but is not optimised for outdoor technical fabrics and may not bond as durably as purpose-made tent DWR products like Nikwax TX Direct or Gear Aid ReviveX. Purpose-made products have formulations designed for the specific coatings used on tent fabrics (polyurethane, silicone, polyester) and are worth using if you want lasting results. For emergency treatment before a trip, Scotchgard is better than nothing.