I have an American Giant sweatshirt that is fantastic. Superb quality and fit. Heavy 10oz cotton. What would be the best way to add water resistance to a garment/fabric normally water resistant? Is it even possible? Could I use a DWR spray? If so, what brand or type? Has anyone had any success doing so themselves? I also researched DIY waxing. However I was unable to find anything other than waxing linen, denim, or rewaxing cotton canvas (jackets and bags).
I’m thinking that waxing would be a bit much for an already heavy cotton sweatshirt?

  • 1
    There are different kinds of waterproofing agents. Some can be used on cotton. Check the label on the one you have - does it say it can be used safely on cotton? If the label says nothing specific, call/tweet/email and ask the manufacturer.
    – ahron
    Commented Jan 10, 2020 at 10:53

2 Answers 2


I suspect that sweatshirt fabric has too open a mesh for any waterproofing agent to be effective. Rather than risk a garment you love, buy as close to a similar weight sweatshirt at a thift store, and do your initial experiments with that.

I have used linseed oil to add water resistance to canvas goods. Look up "DIY Tin pants" on youtube for other recipes. Mixes of linseed oil, turpentine, and beeswax dominate. The 'tin' in waterproofing comes from the former practice of using zinc sterate as an agent.

In passing: I prefer to use a separate wind layer. In winter this is a non-water repellent heavyweight nylon shell with hood. In summer it's a goretex nylon shell. This allow me better control of overheating.

Rain gear is always a tradeoff between getting wet from rain or getting wet from sweat. I am never truly comfortable in rain gear, and will usually only wear it when the alternative is hypothermia. Goretex and their ilk are good in light rains, where the surface of your jacket doesn't film with water. Once you have a continuous film of water, condensation will occur on the inside of that layer.

I've wondered at times of making a jacket out of waterproof fabric in narrow bands overlapped like shingles on a house.

  • Thank you very much Sherwood. The only “proper” rain garment I have is a new shakedry stretchy cycling jacket, which is unreal. I really don’t like rain gear while hiking with the dogs. My American Giant hoodie had become my favorite item of clothing ever. I gues I’m looking to improve on something already phenomenal.
    – Velobuck
    Commented Jan 11, 2020 at 0:05
  • Much depends on temperature. Temps from just above freezing to just below will stress the importance of keeping dry. Anyway: A waterproof breathable fabric will generally work well, and gives you flexibility for extra layers underneath. Or try an umbrella. Commented Jan 11, 2020 at 4:21
  • Great suggestion to test on a different garment. It would be a real shame to ruin a favorite clothing item while trying to improve it.
    – csk
    Commented Jan 14, 2020 at 20:39

There are at least two companies that make cleaning and proofing products specially for outdoor gear of various materials: Nikwax and Grangers. They both recommend first pre-washing the item in their special cleaner -- Nikwax Tech Wash or Grangers Active Wash -- then treating/proofing them (by washing) with Nikwax Cotton Proof or Grangers Clothing Repel. I have not tried either of these.

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