Sustainably waterproofing a rain jacket

Question

My raincoat was fully waterproof when bought some 8 years ago. Now it's like a cotton blouse in that it soaks up water immediately.

I have washed it with technical wash and sprayed it with waterproofing spray. It did not help much so I have sprayed on some more. Surely there must be some more sustainable way.

• The spray can itself is a lot of garbage for a little spray.
• When I spray the jacket a lot of spray does not land on the jacket but goes into the air.
• The spray itself is harmful to the environment.

There must be room for improvement on the first two points. I know there exists a special waterproofing wax, but that means making a bucket of the stuff, soaking the jacket and then throwing out a (bucket - a little) down the drain.

Some dry cleaners also waterproof jackets but I don't know if what they do is less harmful.

Answer 1

What you should consider when trying to refresh the waterrepellency of your garment is how the garment is constructed / was waterproofed originally and which materials were used. There are different types of waterproof garments:

• modern outdoor clothing: Their ability to repel water comes from both a membrane system and an external waterproofing. The membrane has pores that allow single water molecules (aka steam or vapor) from the inside of the clothing to escape while being to small for liquid water (aka rain) to enter from the outside (due to the high surface tension of water). In addition, the outside of the garment is waterproofed with a hydrophobic coating, to prevent the fabric from being soaked in water. This coating can be washed away and needs to be renewed. This is the stuff from the spray can. The problem with using a wash-in hydrophobic coating is that it will also coat the inside of the jacket, which could prevent sweat and moisture from escaping through the pores of the membrane. So although this might seem like a more sustainable option, it is not if the function of the garment is impaired. The biggest problem with these hydrophobic solutions is that they often still contain fluoride compounds that are very damaging to the environment, so if you use this kind of stuff, try to look for fluor-free products. If you buy a new garment, some brands will also already have fluor-free outdoor clothing available.
• plastic based rain gear: Their ability to repel water comes from using plastic coated fabrics or plastic foils. Those garments will not be very breathable, and if they loose their ability to repel water, it will be due to holes, abrasion of polymer material or cracks in the material due to ageing or UV exposure. Spraying those garments with hydrophobic coating will not lead to much improvement, as the spray might not adhere well to the polymer surface. Cuts or holes might be fixed with special tapes.
• waxed cotton: cotton that has been made water repellent by impregnating it with natural or synthetic wax. Those need to be re-waxed from time to time to maintain their properties. Often brands that sell those supply their own wax for maintenance. If used properly, there will be very little wax wastage. If natural wax is used, this is a very sustainable waterproofing method.
• felted wool: densely felted wool garments (boiled wool) will be kind of waterproof because of their structure and the properties of the wool fiber. This can be enhanced by applying additional lanolin regularly. As with the waxed cotton, this is a quite sustainable approach, although these kind of garments will be quite heavy and stiff.

If you try to re-proof outdoor clothing with wax, or cotton with lanolin, or combine any other type of waterproofing with the wrong kind of material, it will not yield usefull results. So before you blindly apply anything make sure you are using the right type of product, otherwise you might damage your garment beyond repair.

Answer 2

Historically in the colonial era, cloth was waterproofed using a 1:1 mixture of boiled linseed oil and beeswax, heated so it would leech into the fibers. For more temporary use, beeswax can sometimes be rubbed directly on the cloth. Linseed oil will provide a much better and more permanent effect, but it is also very flammable.

Jean-Paul Calderone brings up lanolin as an inexpensive method, but I've never seen lanolin sold in a hardware store or supermarket across the United States. One option is to buy a product such as Otterwax, which has lanolin as one of its ingredients and is a waxy substance rubbed directly onto the fabric.

As a side note, washing with lanolin is a great way to decrease the water absorbance of wool fiber and improve its insulation properties.

Answer 3

Lanolin, produced by sheep, has water repellent properties. It is relatively inexpensive and compact. Application is by rubbing or brushing so it doesn't have the waste associated with aerosols. Lanolin has other uses (eg as a skin moisturizer) so having some extra on hand is useful in other ways. It is environmentally innocuous (it will fully biodegrade giving reasonable time and conditions). Related to this, it is also generally regarded as safe (GRAS).

Answer 4

Google search for "wash-in waterproofing". Several are available; Nikwax TX being a popular brand which is at least water-based and PFC free. You use 50ml per garment (hand wash process) so you get more proofing for one bottle than the sprays. Nikwaxare also better than many companies for environmental reporting - see https://www.nikwax.com/en-us/environment/nikwax_and_the_environment.php.

Heat after re-proofing can improve performance cool iron or tumble drying if the jacket allows it). Re-proofing also works much better if done before all the original DWR coating has worn off (might be a bit late for your jacket).