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Spotlight - equipment views and reviews from the AK team

Why do I need to reproof my waterproof?

By Ronnie Legg
26, Jan, 2017

Garment designer Ronnie explains the benefits of regularly cleaning and reproofing your waterproofs

Regularly reproofing your waterproof extends its effective life so that it performs better for longer. Don’t just take my word for it though, Ronnie from the design team is here to explain how and why it works.

For instructions on how to reproof your waterproof garment, read our post on how to reproof your waterproof jacket.

Why do you need to keep fabrics/waterproof membranes clean?

Technical fabrics work best when they are clean. Dirt and contaminants (this could be mud, sweat, body oils, insect repellent, food or even detergent residue) reduce the fabric's ability to repel water or transport moisture. You can't just use regular detergents though, as they often contain additives that attract water, such as surfectants. These additives help to loosen dirt, but work against DWR if not rinsed thoroughly.

The solution is to wash with pure soap or a specialist cleaner like Nikwax Tech Wash. It's important never to use fabric softeners or conditioners on your technical clothing as this will destroy any wicking, repellency and breathability it once had!

A man in a waterproof jacket pouring a cup of water on his head

Do I have to reproof my jacket every time I wash it?

If your garment stops beading up it doesn’t necessarily mean the DWR has worn off. It may just have been temporarily masked by dirt and abrasion, in which case it can be revived. Often you can realign the DWR's molecules and restore performance by giving it a wash and then applying heat, after which the fabric should bead up again. You can apply heat by cool ironing or tumble drying. If the DWR is still not working after washing and heat treating your garment, then it’s time to reproof. 

What does a reproofer actually do?

At a microscopic level, the chain-like molecules of the DWR treatment bind to the surface of the fabric and act like a fringe of spikes or fronds, making water bead up and roll off the surface. Abrasion and contamination of these spikes disrupt their orientation and stop them from working.

Reproofing effectively tops up the factory applied DWR with an off-the-shelf reproofer product such as Nikwax TX Direct. The reproofer works partly by binding to the existing DWR molecules so it’s best not to wait until the whole of the garment is wetting out straight away. For the better results you should reproof when key areas (like the cuffs, sleeves and shoulders) stop beading.

Why do we have to apply heat after treatment?

The factory applied DWR used on current Alpkit products uses C6 technology which is reactivated by heat. Some manufacturers state that their reproofer doesn't need heat curing to be effective; but it doesn't do any harm to the reproofer to heat treat it as well. Plus it will help to revive any remaining C6 DWR on your garment.

To heat treat your garment, you can use a tumble drier on low setting or cool iron it.

Tumble drying is the best option for insulated and down jackets as it will help dry out the insulation at the same time, but bear in mind the mechanical action of a tumble dryer will cause wear and tear to the whole garment each time you do it. For waterproof shells, a cool iron allows you to be more precise with your heat application and limits the mechanical wear and tear. If you are concerned about the fabric you can always place a tea towel between the face of your garment and the iron.

a waterproof jacket with water beading up on the fabric

Which are better, spray-on or wash-in reproofers?

That depends on what you're reproofing! Spray-on reproofers are best for waterproof shells as they allow you to target problem areas and treat only the outer surface of the fabric (which is what you want). For insulated or down garments, wash-in reproofers are better as they will treat the whole garment.

Whichever you use, the key is to reproof when the garment is clean and to use heat to reactivate any remaining C6 DWR.

How often do I need to reproof?

This very much depends on how much you use your gear. The simplest advice is to wash it when it's dirty (or at least 6 monthly) and reproof it when you notice the water starting to bead up. You don’t need to reproof every time you wash, but if in doubt act sooner rather than later. If you leave it too long and wait until the whole garment is wetting out before reproofing, you’ll have a hard time restoring the DWR performance.

I haven't always needed to reproof my garments so often, what's changed?

DWR treatments used to be made with C8 fluorocarbons (PFC), but evidence has shown that this breaks down into PFOA and PFOS which can accumulate in the environment, with negative effects. Several years ago the outdoor industry moved away from using C8 in favour of C6, which does not breakdown into PFOA and PFOS.

The downside of C6 DWR treatments is that the garment's stain resistance and durability are slightly reduced compared to C8, nor is it innocent from an environmental point of view. There are PFC-free DWR treatments available (‘C0’), but they often have zero stain resistance and even less durability.

Why does stain resistance matter? Because dirt and oils (including those from your own body) inhibit the action of DWR. It seems there is a conflict between more environmentally friendly DWR formulations and performance level. The reality is that DWR performance has been reduced in recent years and may continue to reduce until some clever scientists (of which many are working on this precise problem) come up with something better.

So, to sum up...

  • The DWR is what keeps your jacket from getting saturated with water so it stays breathable.

  • Abrasion and dirt can stop your DWR from working properly.

  • Cleaning and heat treating your garment revives the DWR. 

  • If this doesn't work, a reproofer will restore the DWR.

  • Wash-in reproofer is best for insulated jackets and spray-on reproofer is best for waterproof jackets.

  • Heating treat your garment after washing or reproofing helps makes the DWR perform better (with a tumble drier on low for insulated jackets and an iron for waterproofs).

  • The more environmentally friendly DWRs and less durable and stain resistant, C6 DWR is now the most pupular in the outdoor industry.

  • Never use fabric softeners or conditioners on your technical garments! 

Further reading

How to reproof your waterproof clothing

Our step by step instructions for cleaning and reproofing your waterproof garment

How to choose a waterproof to buy

Time to retire your old waterproof and invest in a new one? This guide should help you navigate the plethora of waterproofs on the market

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