When a ‘hard shell’ waterproof garment is first purchased the fabric will perform exactly as per the fabric manufacturer’s benchmark tests. The factory will have applied a treatment known as Durable Water Repellency (DWR), a fluorocarbon-based process that positions molecules on the surface in a way that allows the fabric to actively repel water. You’ll have noticed that pleasing beading effect when water falls on a new garment – it collects and rolls off almost like mercury. It means that the exterior of the fabric is remaining dry and able to fulfill its role of carrying moisture vapour from the interior through to the atmosphere. This DWR treatment is designed to remain effective through many cycles of machine washing.

In time your garment fabric is attacked from several different directions. Externally, abrasion will affect the ‘face’ of the fabric, pulling fibres loose and microscopically ‘furring’ the exterior weave. This affects the surface tension of water that lands on the fabric, holds dirt more efficiently and generally degrades the ability of the DWR treatment to repel water.

Internally, even though you’re often not wearing the fabric next to the skin, oils excreted by your body are carried in perspiration vapour through the interior structure of the fabric and deposited inside the coating or membrane. Because these coatings and membranes are the key technologies that allow the fabric to transmit moisture vapour to the outside, any contamination will affect their ability to perform.

So assailed from both sides, modern ‘wonder fabrics’ can begin to lose their original performance. And it’s not just clothing – increasingly boots are constructed using waterproof/breathable membranes and become affected in similar ways.

What to do? Well, the obvious first step is to wash garments. Check the manufacturer’s care guidelines and never use detergents as they are aggressive and seriously affect the fabric. Use of Granger’s products followed by the application of heat to ‘re-set’ the DWR treatment will leave the garment performing as new.

This entirely depends on the fabric used by your garment manufacturer. Some are extremely good and last over 10 machine washes, while others will need attention sooner. It also depends on usage – if you’re a mountain guide and out every day the garment will get more of a hammering. Generally, just wash according to the garment guidelines until you feel the water repellency is not lasting long enough, then re-proof.

Again, this depends on the proofing product and garment usage. Granger’s proofing technologies replicate the DWR formulation originally applied by fabric manufacturers, so this effectively just restores the original treatment. Logically this should help the garment to retain its water repellency for longer.

Soft shell fabric technologies also rely on DWR treatments to keep water out, and exactly the same advice applies. Maintaining water repellency is often more essential than with hard shell garments - hard shells usually keep exterior water out even when the DWR is shot, but soft shells really need to retain their water repellency to keep you dry. Apply Granger’s re-proofing products the minute you find that washing is not enough to maintain water beading on the outside.

With footwear it’s more a question of keeping the outside of the boot clean and using a care treatment that’s specifically designed for the construction, eg. leather or fabric. This maintains the material and gives any internal waterproof/breathable technologies a better chance of retaining their performance.

Gloves are similar to boots in that they can be constructed using a waterproof/breathable insert. As the insert is hidden within the product’s construction you can’t directly apply a treatment but keeping gloves and boots clean using manufacturer’s instructions will make sure they give their best for longer.

Other gear that requires cleaning and looking after includes tents and rucksacks. Tents are increasingly making use of lightweight fabric technologies that reduce pack weight and rely on effective DWR treatments to keep water at bay. While breathability is not an issue in the same way as garments, dirt and dust will affect the fabric’s ability to repel water and looking after your flysheet will pay dividends.

Rucksacks clearly are not protecting you directly from the elements (unless you’re really in trouble!) but they do protect your gear, including stuff that must remain dry. Very few rucksacks are actually designed to be waterproof using sealed seams, but they do use waterproof coated fabrics which will last longer if kept clean.

Rucksacks and tent flysheets can be fully immersed and washed using Granger's Wash-in Cleaner Plus, by hand or in a washing machine. If using a washing machine we advise placing the item in an old pillow case for the wash cycle.

If a rucksacks or flysheet is particularly soiled in a certain area, use Granger’s Cleaner Plus to spot-clean. Simply apply a 50% cleaner/water mix onto a clean cloth and gently work into the soiled area. Make sure you wash the entire surface straight after applying the treatment. Remove any cleaning residue with a clean damp cloth.

Allow the rucksack or flysheet to dry completely before applying Fabsil or Fabsil Gold.

Yes, without a doubt. Granger’s products are water-based and use the same fluorocarbon technology as fabric manufacturers - independent tests have shown they do not contain any harmful compounds.