How to Design a Garden Room Gym

A garden room gym works when four things are designed in from the start: a floor that takes dropped weights and heavy machines, a ceiling high enough to press overhead, ventilation that actually moves air, and heating and glazing that keep the room usable in February without turning it into a greenhouse in July. Get those four right and a garden gym is the room that gets used every day. Miss one and it becomes storage within a year.

This is how we approach the gym version of our hardwood garden rooms, and what to decide before any drawing is made.

How big does a garden room gym need to be?

Bigger than most people first sketch. A rowing machine is around 2.4 metres long in use. A treadmill needs its own length plus clearance behind it. A squat rack with a barbell needs a 2.2 metre bar width plus room to load plates at each end, so 3 metres of clear width. A yoga mat with space to move around it is 2 metres by 1.5 metres.

As a working rule:

• A cardio and mat gym for one person: from around 3 metres by 3 metres.

• A rack, a bench, a cardio machine and floor space: 4 metres by 3 metres upwards.

• A gym for two people to train at the same time: 5 metres by 3.5 metres or more.

Height matters as much as floor area. Overhead pressing, pull-ups, skipping and a rack with a pull-up bar all want a clear internal height of at least 2.4 metres, and 2.6 metres is more comfortable. That interacts with the planning rules on height, covered below, and is the main reason a gym should sit away from the garden boundaries.

What floor does a garden gym need?

The floor is the part that separates a gym from any other garden room. Two things are being asked of it: to carry concentrated loads, and to survive impact.

A standard garden room floor built on a timber frame over pads is designed for people and furniture. A loaded rack with a lifter under it can concentrate several hundred kilograms on a small area, and a dropped barbell delivers a shock load far above its static weight. For a serious weights room we build on an insulated concrete slab, which also gives the room thermal mass and a floor that does not bounce. For a cardio and mat room a well-designed timber floor with additional joists under the equipment positions is adequate.

Over the structure goes a resilient finish. Rubber gym tiles of 20 to 30 millimetres protect both the floor and the joints of the person on it. Under a lifting platform, thicker tiles or a bonded rubber crumb mat over plywood take the impact and cut the noise transmitted through the ground to the house and the neighbours.

Plan the machine positions before the floor is built, so the strengthening goes where the loads will be.

How do you ventilate a garden room gym?

Ventilation is the most under-designed element of every garden gym we are asked to look at. A person training hard produces a great deal of heat and moisture in a small, well-sealed room, and trickle vents in the windows will not deal with it. Condensation on cold glass in winter and stale, hot air in summer are the results.

The answer is designed cross ventilation plus mechanical extract. Opening windows or doors on two opposite elevations let air move through the room. A quiet extract fan, sized for the room volume and switched with a humidistat, removes moisture whether the windows are open or not. In a fully glazed room, roof vents that open automatically on temperature are worth specifying.

Air conditioning is a reasonable addition in a gym that is used hard through the summer, and a heat pump unit doubles as heating in winter. It is a great deal easier to install during the build than afterwards.

Glazing and heating for a gym

Glass gives the garden gym its appeal: training with a view of the garden rather than a wall. It also brings glare and heat, which the specification has to solve.

Put the main glazing on the elevation facing the garden and away from the afternoon sun where the site allows. Use solar control glass on south and west elevations and in any roof glazing, and fit blinds or external shading where the view is worth keeping but the sun is not. A solid section of roof over the main training area gives shade where the effort happens.

For heating, underfloor heating in a concrete slab is quiet and invisible, and a wall-mounted heat pump unit heats quickly, cools in summer and takes no floor space. Insulate the floor, walls and roof properly: an uninsulated glass box is unusable for half the year.

Does a garden gym need planning permission?

Usually not in England: a garden gym is an outbuilding, and it is permitted development if it stays within the outbuilding size, height and position limits. The limit that matters most for a gym is height. Within 2 metres of a boundary the whole building can be no more than 2.5 metres high, which is tight for a gym with overhead lifts, so a gym is usually sited away from the fences. The full rules, including building regulations and the exceptions for listed buildings and designated land, are in our guide to garden room planning permission.

Noise, mirrors and the details

Noise is the neighbourly issue. A dropped deadlift on a timber floor is heard three gardens away; on a slab under thick rubber it is a dull thud. Music through a wall of glass carries. Site the gym so the solid wall faces the nearest neighbour and the glass faces your own garden.

A mirror wall on the solid elevation doubles the apparent size of the room and is the single most gym-like thing you can add. Wire it with lighting above rather than opposite, so the mirror does not reflect glare from the glazing.

Include more sockets than seem necessary, a data connection for screens and trackers, a tap outside the door and a bench by the entrance for shoes. Plan storage for plates and bands along the solid wall so the floor stays clear.

Of all the garden room ideas clients bring to us, a gym is the most demanding to build well, and the most rewarding when it is.

Garden room gym questions, answered

Can a garden room floor take gym equipment?

A standard timber garden room floor takes cardio machines and mats. Racks, heavy free weights and dropped barbells need a strengthened floor or an insulated concrete slab, with a rubber finish over it.

How do you stop a garden gym getting too hot?

Solar control glass, shading, cross ventilation and an extract fan on a humidistat, with a heat pump unit that also cools for hard summer use.

Is a glass garden room suitable for a gym?

Yes, if the glazing is specified for it. Solar control glass, a partly solid roof, proper insulation and designed ventilation turn a glass room into a comfortable gym. A fully glazed, unshaded box is not.

Talk to our design team

If a garden gym is on your list, talk to us about your project and we will design the glazing and ventilation around the way you train.