Have you ever busted out your rain gear only to get soaked and find out that it is no longer waterproof? Or have you found that your jacket has become mysteriously sticky and flaky? No need to fear, when your jacket becomes sticky or the internal coating flakes off, this is just the urethane coating starting to break down. This breakdown process is called delamination and generally starts to happen around 7-10 years of age, depending on the use and storage of the product. This is part of a jacket's natural life cycle and will happen at some point to all jackets. It is not a manufacturing defect.
From here you have 3 options:
1. Leave the jacket as is with no waterproof coating.
2. Treat the outside of the jacket with a DWR spray which will make it water resistant.
3. Re-waterproof the jacket, by treating the inside with your choice of waterproofing agent, such as Revivex or a gear-aid product. Follow instructions on the packaging to apply.
The good news is that it's possible to repair this at home by doing the following:
1. Turn the jacket inside out then soak in cool water with an unscented laundry detergent for about 30 min (the laundry detergent will break down the coating).
2. Allow the jacket to dry completely.
3. Take a bristle brush and scrub the jacket to remove the flakes that may be present. For difficult spots, you can use rubbing alcohol.
4. Rinse thoroughly and air dry.
For more information, check out this online tutorial: Gear Aid How to Waterproof a Jacket