How to Seam Seal a Tent

A person seam seals a tent

Is water coming in through the seams of your tent? Or are those seams just beginning to peel away? If so, you don’t need to shell out your hard-earned cash on a new shelter – you just need to learn how to seam seal a tent!

Seam sealing a tent can help immeasurably with re-waterproofing your tent – and learning how to seam seal a tent is surprisingly easy. Here’s how to do it.

How to seam seal a tent – quick guide

Prep/seam cleaning time: 5 mins (without cleaning the whole tent)
Application time: 5-10 minutes/seam
Drying time: 12 hours

  1. Before sealing, clean the seam with rubbing alcohol and let dry
  2. Gently squeeze the sealant along the length of the affected seam
  3. Leave sealant to dry for at least 12 hours before use

What you’ll need

How to seam seal a tent in three easy steps

1. Clean the seam

Before you seam seal your tent, clean the seam in question with rubbing alcohol on a small flannel and let it dry fully. 

cleaning the seams of a tent with rubbing alcohol is an important process in learning how to seam seal a tent
Cleaning the seam with a small flannel and rubbing alcohol before sealing will ensure no debris gets caught in the sealant

If the main body of your tent is dirty, we’d recommend cleaning the whole area in a body of lukewarm water with a mild dish soap or Nikwax Tech Wash before seam sealing your tent.

This ensures that no dirt or debris will contaminate the area you’re trying to fix.

2. Apply Sealant

Once you’ve cleaned the seam with rubbing alcohol, gently squeeze the sealant along the length of the affected seam (you can do this with or without the brush attached). Do this on both the inside and outside surfaces of the seam.

a person seam seals a tent
With seam sealant, a little goes a long way – squeeze the tube gently as you move it along the seam

The coating of the materials may be different on the inner and outer surfaces of your tent’s seams, so check on the manufacturer’s website (or on online forums) for more detailed information on the specifics of your tent, as this’ll affect what seam sealant you need to use.

Make sure that the seam is completely flat when you’re applying the seam sealant. Accidentally applying sealant over folds in the fabric could damage the material when separating those folds (when the material becomes taut in the tent set-up process, for example).

a person uses a brush to evenly distribute seam sealant along the seam of a tent
Brushing thick patches of seam sealant along the seams ensures even distribution

If necessary, use the brush attachment to distribute thickly-coated patches of seam sealant along the seams. 

3. Wait before use

Having successfully completed the seam sealing process, leave the seam sealant to dry for at least 12 hours before using your tent. 

The makers of the seam sealant I used on my sil/poly tent recommend that you let it set in temperatures of 60F/15C or above. As I’m in Britain (in November), this requires some doing – so I put it in an airing cupboard – making sure that none of the tent folded over onto the seam on which I’d applied the sealant.

Important information on tent materials

Not all tents are made from the same material – so different materials will require different seam sealant to work (i.e. seam sealant designed for silicone-based materials won’t work on polyurethane-based materials).

Some tents (like Gossamer Gear’s The One, for example) are, somewhat confusingly, made with a SIL/PU (or “sil-poly”) fabric – i.e. a combination of both materials. This, naturally, makes seam sealing difficult. Despite my extensive research, I haven’t been able to find out which side of the tent (i.e. the inner or the outer) is coated with silicone, and which side is polyurethane.

If your tent is made from sil-poly and you need to seam seal it, the best course of action is to contact the manufacturer directly and ask them which seam sealant to use for your particular tent.

Finding the material that your tent is made from is relatively simple. If it doesn’t show it on the little warranty tag that’s sewn somewhere inside your tent, you’ll be able to find it out on the manufacturer’s website.

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