Why waterproof jackets stop working

A good waterproof jacket rarely fails all at once. Most of the time it loses performance slowly, and the owner blames the jacket rather than the care. Two separate systems are at work. The first is the membrane, a thin layer of expanded polythene or polyurethane that stops rain coming in while letting some vapour escape. The second is the durable water repellent finish, usually called DWR, which sits on the outer face fabric and makes raindrops bead up and roll off.

When the DWR wears out, the face fabric starts to soak up water like a sponge. The jacket is still waterproof, but it feels cold, heavy and clammy, and breathability drops because vapour can no longer pass through the saturated outer layer. Worse still, dirt, sweat salts, sun cream and body oils clog the fabric and gradually break down both the DWR and, eventually, the membrane itself. The fix is not a new jacket. It is a wash, a reproof and a bit of regular attention.

Washing a jacket properly

Washing a technical jacket feels wrong, but it is the single most effective thing you can do for it. Grime masks the DWR and holds water against the fabric. As a rough rule, wash after every ten to fifteen days of hard use, or whenever the jacket wets out across the shoulders and chest rather than beading.

• Check the care label and close all zips, flaps and Velcro tabs. Fasten the hood adjusters.
• Use a specialist technical wash, or at a push a pure soap flakes product. Never use biological powder, fabric conditioner or ordinary detergent, which leave residues that attract water and can strip coatings.
• Wash on a gentle cycle at 30°C with a low spin. A front-loading drum is fine; avoid top loaders with an agitator.
• Rinse twice if your machine allows it. This flushes out the last of the detergent.
• Never dry clean a waterproof jacket unless the label specifically says it is safe.

If the jacket is heavily soiled around the collar and cuffs, sponge those areas with a little tech wash before the main cycle. Do not scrub with a stiff brush, which abrades the face fabric and the seam tape underneath.

Reactivating and renewing the water repellency

Many people reproof when they simply needed heat. The DWR on most modern jackets is heat-activated, so after washing, tumble dry on a low setting for twenty to thirty minutes. If you do not own a dryer, iron the jacket on the lowest setting with a clean cloth between the iron and the fabric, keeping the iron moving. You will often see the beading return within minutes.

If heat alone does not work, the DWR has genuinely worn away and needs replacing. Choose a spray-on proofer for jackets with a lining or a warm backer, and a wash-in proofer for simple shell garments. Spray-on gives you more control and avoids coating the inside of the jacket, which can reduce breathability. Hang the jacket, spray evenly from about 20cm, pay extra attention to shoulders, sleeves and the hood, then tumble dry low or hang to dry as the instructions direct. One careful treatment usually lasts a full season.

Repairing tears, zips and seams

Small damage grows quickly in wind and rain, so deal with it at home rather than on the hill. A pinprick tear in the face fabric can be fixed with a peel-and-stick repair patch, rounded at the corners to stop it lifting. Clean and dry the area first, press firmly, and avoid stretching the patch over a seam. For larger rips, a flexible seam sealant or a sew-free adhesive patch will hold for years if applied patiently.

• Lifting seam tape can be re-bonded with a warm iron over a cloth, or sealed with a little flexible seam sealant.
• Sticky zips respond well to a silicone or wax lubricant. Never use oil, which collects grit.
• Broken zip pulls can often be replaced without a full zip swap; a repair specialist can do this cheaply.
• Worn cuff tabs and frayed drawcords are easy sewing jobs that stop the damage spreading.

Carry a couple of patches and a small length of cord in your rucksack repair kit. A ten-minute fix at the car boot saves a jacket.

Storing it well between adventures

How you store a jacket matters as much as how you wash it. Never leave a damp jacket compressed in a stuff sack for weeks. Hang it on a wide hanger in a dry, airy place, away from radiators, hot water tanks and direct sunlight, all of which degrade coatings and seam tape. If space is tight, fold loosely rather than cramming it into a cupboard.

Before it goes away for the season, give it a wash and a fresh reproof, then hang it. Mud, salt and sweat left on fabric over summer do quiet, cumulative damage. A little routine care, once or twice a year, will keep a well-made jacket working hard for a decade of fells, coast paths and wet Welsh weekends.