Planning a home bouldering wall: space, angle and fall zone

A home wall is the climbing equivalent of a home gym: a small, steep board you can hop on for half an hour on a wet Tuesday. Built well, it will keep you strong through a Wellington winter or a West Coast wet spell. Built badly, it wastes plywood, annoys whoever else uses the garage, and puts you at risk of landing on concrete.

This note is about planning, before you buy any timber. Most of the decisions that make a wall good or bad are made with a tape measure and a notepad, not a drill.

What a home wall actually is

Commercial walls and home walls work the same way. As the Wikipedia article on climbing walls explains, most are thick plywood boards drilled with holes. Each hole holds a T-nut, a threaded insert, so holds can be bolted on and moved around. Smaller holds can be screwed straight into the ply. The simplest wooden version is often called a "woody". At home that usually means one to three sheets of ply on a timber frame, set at an overhanging angle, with a spread of small holds.

Garage, carport or freestanding?

Inside a garage is the most common choice. It keeps the wall dry and lets you climb at night. The limits are height and the existing structure. Many garages have a low ceiling, roof framing that was never designed for extra loads, and a door that needs room to open.

Under a carport gives you more height and better airflow, but the wall and your pads are exposed to wind-blown rain and sun. Plan for exterior-grade materials and more upkeep.

Freestanding means a self-supporting frame in a shed, a garage or the backyard. It avoids hanging loads off the house, but it needs a properly designed frame that can't rack or tip, and an outdoor one needs serious weather protection.

Whichever you choose, the building is part of the structure as soon as the wall is fixed to it. Our upcoming notes on framing go into that. For now, note which walls, beams and ceiling framing you would be relying on.

Choosing an angle

Angle is the biggest decision you'll make. Vertical walls are easy on fingers but quickly get boring. Very steep walls are powerful training, but small holds become unusable and beginners struggle to get off the ground.

Many home walls sit somewhere around 30 to 45 degrees past vertical, which is steep enough that small holds feel hard, but not so steep that everything turns into a roof. If more than one person will use the wall, and especially if anyone is a beginner or a child, lean towards the less steep end. Some builders add a short vertical "kicker" panel at the bottom, which gives better footholds and a more natural start.

Remember that a steeper wall needs more depth. The top of a 45-degree wall sits a long way out from its base. Draw the wall to scale on paper, with its height and angle, to see how much floor it really takes up.

The fall zone

The fall zone is the floor you will land on, and it is the most important part of the plan. On an overhanging wall you fall out and backwards, often further from the wall than you expect. The fall zone should be:

• Completely clear of cars, benches, tools, shelving and anything with corners.
• Big enough to cover the whole area under the wall plus a generous margin behind and to the sides.
• Covered in proper padding from edge to edge, with no gaps where an ankle can drop through.

A real crash pad or thick gym-style matting is the minimum. Bed mattresses and camping mats bottom out and slide. The Wikipedia article on bouldering describes how crash pads protect climbers from short falls. At home you have the advantage of being able to cover the whole floor, so do it.

Keep the top of the wall low enough that a fall from the highest hold is a fall you are happy to take onto your padding. On a home wall, the top holds are usually around two and a half to three metres off the ground. Higher than that rarely adds much training value and makes every fall worse.

Fitting into a shared space

A garage wall has to share space with whatever else lives there. Think about:

• Light. You need good, even light on the holds, and no low hanging fittings where your head goes.
• Air. Garages get damp and stuffy. Ventilation helps your skin, keeps chalk dust down and protects your pads and shoes from mould.
• Noise. Falls make a thump, and some neighbours share walls.
• Storage. Have a plan for the holds you aren't using and for the pads when the car is inside.

Consent and the existing building

In New Zealand, some low-risk building work doesn't need a building consent, but exempt work still has to comply with the Building Code. A wall that adds loads to an existing structure, or a large freestanding frame, may or may not fall within an exemption depending on its size, height and what it's attached to. Ask your council early. If the wall will hang off rafters, ceiling joists or a garage's wall framing, have a chartered structural engineer look at it. A short consultation costs far less than repairing a sagging roof or landing in the wreckage of a wall.

Plan on paper first

Before you buy anything, draw:

1. A side view showing the wall height, angle, kicker and fall zone.
2. A floor plan showing pads, the car, the garage door and storage.
3. A note of which parts of the existing building the wall will rely on.

With those three drawings you can have useful conversations with your council or an engineer, get accurate material quantities, and spot problems while they are still cheap to fix. For a sense of how holds turn into competition-style problems once the wall is up, see how bouldering comps are scored.