The Outdoor Bouldering Kit List: What a Crash Pad, a Brush, and Approach Shoes Actually Do

Indoor bouldering requires shoes, chalk, and the ability to pay the day fee. Outdoor bouldering requires those plus a crash pad, a brush, approach footwear, and some grasp of the environment you are moving through. The gear list is short, but each item has specific functionality that is not obvious from specifications alone.

The Crash Pad

A crash pad is a portable folding mat that you place on the ground beneath a boulder problem to absorb the impact of falls. It is the most expensive and most important piece of outdoor bouldering gear, and the distinctions between pad designs matter.

Foam construction. Almost all pads use two foam layers with distinct properties.

The bottom layer is closed-cell foam — dense, firm, and resistant to compression. Its purpose is to distribute the impact of a landing across a wider surface area and prevent the pad from "bottoming out" on hard ground. When you land on a crash pad, the bottom layer is doing the structural work of stopping you from hitting the rock or earth below. This foam is heavier and more rigid; you can feel its firmness when you press on the bottom of the pad.

The top layer is open-cell foam — softer, more compressible, and designed to absorb the last phase of impact. It cushions the final deceleration. Open-cell foam is the layer that makes the difference between landing on something that feels controlled and landing on something that jars. This foam compresses more visibly and feels softer.

The balance between the two layers is where pad designs diverge. A pad with too much open-cell foam on top feels soft on casual contact but bottoms out on hard landings from height. A pad with too much closed-cell foam is firm throughout and does not absorb the way it should. High-quality pads have enough of each layer to serve both functions; budget pads often compromise the open-cell layer to reduce cost.

Fold type. Pads fold in two ways.

A hinge-fold pad folds flat along one central crease, like a book. The hinge creates a straight seam that runs across the middle of the pad surface; when unfolded, this seam lies across your landing zone. Hinge-fold pads are typically thicker on either side of the hinge and fold cleanly for transport.

A taco-fold pad (also called a clam-shell) opens in a curved fold, like a taco or clam. The landing surface is continuous — no central seam — which is an advantage for landing zones where the hinge crease of a hinge-fold pad might direct a fall awkwardly. Taco-fold pads are often preferred for low-angle problems or landings that cover the full pad surface; hinge-fold pads are more common for general-purpose use.

The fold type matters more on problems where the crux landing zone is small and specific. For general use — moving one or two pads between problems at a crag — the difference is secondary to foam quality and pad size.

Size. Pad dimensions vary significantly. A standard full-pad is roughly 120 × 90 cm in landing surface, with foam thickness between 10 and 15 cm. Half-pads or mini-pads are smaller — approximately 80 × 60 cm — and are designed as supplements to a full pad rather than standalone protection for high or committing problems.

A single full pad is the minimum useful setup for most outdoor bouldering. Two pads — stacked or positioned side by side depending on the problem's landing zone — cover more area and are standard for any problem with a significant fall height or awkward landing. Spotter positioning (see below) fills the gaps between pads.

Weight. A quality full crash pad weighs approximately 8–14 kg depending on foam volume and shell material. This is the pad on your back during the approach. Crag approaches to bouldering areas vary from a 5-minute flat walk (Fontainebleau in the Seine-et-Marne forests south of Paris is the archetype — most problems are directly roadside or a few hundred metres into the forest) to a 90-minute steep hike. The weight of the pad you are willing to carry is genuinely limited by approach distance. Many climbers maintain a lighter pad for long approaches and a heavier full pad for closer access crags.

Backpack straps are standard on all pads. Better-designed pads have shoulder strap systems with a sternum strap and a waist belt that transfer weight to the hips for longer approaches. The harness system on a crash pad is worth examining before purchase; a pad that is miserable to carry on a 45-minute approach will deter you from using it.

The Brush

A stiff-bristle brush — typically boar's hair or synthetic nylon — is used to clean holds before and during attempts on a problem. Chalk, skin oil, rubber residue from shoes, and organic material (lichen, dust) accumulate on outdoor rock holds over time and degrade friction. Brushing removes this buildup and exposes clean rock texture.

The etiquette around brushing is worth understanding. Cleaning holds before you attempt them is standard and expected. Applying excessive chalk to holds — particularly on overhangs where chalk cakes thickly — is less welcome. Some bouldering communities brush holds aggressively clean after sessions precisely because chalk accumulation alters friction for subsequent visitors.

Tick marks are small chalk dots climbers apply to mark hold positions when learning a problem's sequence. They are accepted practice in most areas. They should be brushed off before leaving — tick marks that remain on the rock through multiple sessions become permanent chalk smears and are considered disrespectful to subsequent visitors and to the rock. Brush them off each session before you leave.

Hard rock types (granite, sandstone, gneiss) can be brushed firmly. Soft or friable rock (some limestone, shale, volcanic tufa) should be brushed more lightly; aggressive brushing can damage holds on soft rock. Know what you are on.

The walk from the car or trail to the boulders is typically off-trail, sometimes across rock slabs, roots, or rough terrain. Your climbing shoes are not designed for this. Approach shoes — a category between trail running shoe and lightweight hiking boot — provide the grip and support for the approach without the weight and ankle restriction of a hiking boot.

Most approach shoes have a sticky rubber sole with a rand that allows smearing on rock slabs in the approach itself. If the crag approach involves scrambling over clean granite or sandstone, a good approach shoe sole is genuinely useful — the rubber performs much like a climbing shoe on low-angle slabs without requiring you to change into climbing shoes for every flat rock section.

Trail running shoes work as a substitute for approaches that are purely trail-based. For approaches that involve significant rock scrambling, a dedicated approach shoe is worth the additional specificity.

Chalk and Chalk Bags

Standard chalk (magnesium carbonate) is the same outdoors as indoors. The chalk bag you use on indoor problems works outdoors. Many outdoor boulderers switch to a chalk bucket — a wider, open-top container that sits on the ground near the problem rather than strapping to the body — because it accommodates both hands for chalk application and is more stable on the ground next to the pad. Buckets are not useful for dynamic movement problems where you need chalk access during the sequence; for those, a standard chalk bag worn on a belt is more practical.

Liquid chalk is a chalk-alcohol suspension that dries on the hands and creates a base layer of friction before any loose chalk is applied. It is particularly useful in humid conditions, on problems with smooth or polished holds, and for skin surfaces that do not hold dry chalk well. Apply it at the beginning of a session and top up with dry chalk during attempts.

The Spotter

The person standing behind you while you climb a boulder problem — the spotter — is not a catcher. They are not attempting to hold your body weight. Their function is to redirect a falling climber's trajectory toward the pad and away from rock, bad landings, or the pad's edges. A good spotter watches where the climber's hips and lower back are during the fall — the body's centre of mass — and positions to guide, not stop, the descent.

Two common spotter errors: standing too close (which interferes with the climber and does not allow adjustment of position when the fall happens unexpectedly) and looking at the climber's hands rather than hips (which leads to reaction time that is too slow when the climber actually falls). Spotting is a practiced skill and worth doing with attention.

No amount of crash pad covers bad spotter positioning. Pads can be moved to close gaps; spotters fill the rest.