Wet-Out
Wet-out is when a shell's outer face fabric becomes saturated, which stops water vapour escaping and makes the jacket feel like it is leaking when it is not.
The membrane or coating is still holding liquid water out. What has stopped is breathability, because vapour cannot cross a layer of liquid water sitting in the face fabric. The dampness you feel on the inside is your own condensed sweat.
Why it feels like a leak
The inside of the jacket gets wet, which is exactly what a leak feels like. The tell is where the wetness is. A leak shows up at seams, zips and the hood, in patches, and usually on the outside of your base layer. Condensation from wet-out is even, appears across your chest and back, and is worse the harder you were working.
What causes it
A worn or dirty DWR finish. When the water repellent finish is intact, rain beads and rolls off the face fabric, which stays dry and keeps passing vapour. When it wears down, the fabric absorbs instead.
Heavy sustained rain will eventually wet out almost any face fabric, even a new one. Good DWR delays it, it does not prevent it forever.
What to do about it
In the field: open vents, slow down, reduce how much vapour you are producing. There is no way to un-saturate a fabric while it is raining on you.
At home: clean the garment and reapply DWR. Most jackets that people believe have failed simply need reproofing.
Related terms
- DWR: the finish that prevents wet-out
- How to wash a waterproof jacket: the reproofing method
- Waterproof and breathability ratings explained: why breathability figures collapse in the rain
- Glossary: all terms