Rab Firewall Mountain Review: A Versatile Waterproof Mountain Jacket

Introduction

The Rab Firewall Mountain is a three-layer waterproof shell built for people who want one jacket that handles a wide range of mountain conditions without paying top-tier money. It sits in a useful middle ground: softer and quieter than the stiff, highly protective shells at the top of the market, but far more rugged than a stripped-back emergency layer. The fabric is Pertex Shield, a membrane Rab has used across several jackets over the years, and here it is paired with a 40 denier recycled face fabric and a backer that adds durability and helps move moisture away from the body.

The result is a jacket designed to be worn all day rather than carried just in case.

Who This Jacket Is For

This is an all-rounder for hill walking and longer days out, with enough capability to handle a scramble or an easy climb where a helmet goes on. The hood takes a helmet and cinches down properly when it is not needed, so it works for both walking and more technical outings.

It is not pitched as a dedicated winter climbing jacket, though it can be used in colder conditions with layers underneath. The appeal is versatility: one shell that covers walking, scrambling and easier climbing without the price tag of a top-end mountaineering jacket.

Main Strengths

The strengths of the Firewall Mountain come down to three areas: the fabric and its weather performance, the fit and coverage, and the feature set.

Weather Protection and Fabric Performance

Pertex Shield is used here in a three-layer construction. The visible layer is a 40 denier 100% recycled face fabric that gives the jacket its rugged feel, the membrane sits in the middle, and a backer adds durability and helps move moisture. The headline numbers are a 20,000 mm hydrostatic head and a 20,000 vapor transfer rate, so it should keep rain out while remaining reasonably breathable. Those figures come in a little below top-tier membranes, but the practical difference is likely to be hard to notice on a normal day out.

Just as important is how the fabric feels. It is soft, supple and noticeably quieter than many waterproof shells, which makes it comfortable to wear for long periods rather than something you simply tolerate. The material is also PFAS free, with no fluorocarbon-based chemistry in the finish.

Fit, Sizing, and Coverage

The jacket is long. It drops well below the belt and covers the seat, which gives useful extra protection for walkers who spend long hours in wind and rain. Cuffs use Velcro closures that are easy to adjust with gloves on and roomy enough to fit over a glove cuff.

Sizing runs generous. A wearer around 6 ft 4 in and 90 kg found a large left plenty of space for multiple layers, making it a realistic option for both summer and winter use.

Pockets, Zips, and Ventilation

There are three pockets: a Napoleon-style chest pocket on the left that will take a phone and snacks, plus two large hand pockets that can hold a map, gloves and hands. All of them, along with the main zip, use YKK AquaGuard zips, which are reliable and water resistant.

The main zip is two-way and finished with a large pull cord that is easy to grab with gloves. A popper at the bottom lets you leave the jacket partly open while still staying protected from above, which pushes a lot of air through the shell. The pit zips are large and have two sliders each, so you can open them as much as you need. A double pull cord on the hem lets you cinch the jacket down when you take layers off or want to stop wind blowing up underneath.

Things to Consider Before Buying

The PFAS-free finish is a genuine plus for the environment, but it does mean the jacket may need washing and reproofing more regularly than older fluorocarbon-treated shells. Looking after it properly will keep it performing well for longer.

At 492 g for a medium, it is neither the lightest nor the heaviest jacket in this class. It packs down reasonably small for how rugged the fabric is, but it is not a stripped-back emergency shell.

The sizing is on the generous side, so it is worth trying before committing if you prefer a closer fit. And while the hood and cuffs make the jacket capable of more technical use, it is not positioned as a full-on winter climbing jacket.

Buying Advice

If you want one waterproof jacket to cover walking, scrambling and easier climbing, the Firewall Mountain makes a strong case for itself. It offers the feature set of far more expensive shells, including a helmet-compatible hood, three pockets, AquaGuard zips, large pit zips and a long cut, at roughly half the price of top-end Gore-Tex mountain jackets.

The trade-offs are the ones you would expect at this level: slightly lower waterproof and breathability figures than the most expensive membranes, a finish that needs more frequent care, and sizing that runs large. None of those undercut the value proposition, and for most hill walkers the performance gap will not be noticeable in real use. If you want a protective, comfortable shell that handles a wide range of conditions, this is a sensible place to spend your money.

Conclusion

The Rab Firewall Mountain is a genuinely versatile waterproof jacket. Pertex Shield keeps it soft, quiet and comfortable, the 40 denier recycled face fabric keeps it rugged, and the feature list matches jackets that cost considerably more. It is a well-judged all-rounder for walkers and scramblers who want protection and comfort without the premium price.