Hardshell
A hardshell is a non-insulating waterproof outer layer built on a membrane or coating, designed to block wind and rain and nothing else.
It provides essentially no warmth. That is the point: because it insulates nothing, it stacks over whatever the temperature demands, which is what lets one jacket cover a wide climate range from a small bag.
What defines one
A face fabric bonded to a waterproof layer, taped seams, and no insulation. Builds are described as 2-layer, 2.5-layer or 3-layer depending on what protects the membrane on the inside. Waterproofing is quoted as hydrostatic head in millimetres.
Strengths
It is the only layer that fails catastrophically rather than inconveniently, so it is the one worth spending on. It packs small, blocks wind completely, and layers cleanly over anything. For a carry-on crossing climates it is the default outer layer.
Weaknesses
Limited breathability under exertion, and almost none once the face fabric wets out. It is noisier and less comfortable than a softshell, and it reads as equipment rather than clothing, which matters in some cities more than others.
Related terms
- Softshell vs hardshell for travel: the choice by trip type
- 2-layer, 2.5-layer and 3-layer shells: how hardshells are built
- Wet-out: the limit on hardshell breathability
- Glossary: all terms