How to Build a Gym in the Garden: A Step-by-Step Guide

Ditch the sweaty commutes and crowded benches—building a garden gym is your ticket to hassle-free, anytime workouts just steps from your back door. Short answer? Plan your space, build a sturdy shed, weatherproof it, add power and kit it out. Keep reading for all the smart, budget-friendly steps!

Why a Garden Gym?

Let’s be honest — the local gym isn’t always a vibe. Peak-hour crowds, smelly changing rooms, and eye-watering membership costs. With a garden gym, you’ve got:

Privacy: Train how you want, when you want.

Convenience: Your commute is now ten seconds.

Cost-effectiveness: No more monthly payments. Just one upfront investment.

Dedicated space: No clutter, no distractions — just you and your goals.

It’s your health, your rules.

Project Overview

This isn’t just about plonking a treadmill in a shed. You’re creating a purpose-built fitness haven — and that means getting three things right:

Planning: Define your needs, layout, and budget.
Construction: Build a shell that’s warm, waterproof, and rock-solid.
Fit-out: Kit it out with the right gear and finish it beautifully.

Each stage matters. Skimp on one, and you’ll feel it down the line — whether it's freezing workouts in winter or saggy floors under your squat rack.

Stage 1: Planning & Design (The Foundation of Success)

1. Define Your Gym Needs & Goals

Start with a vision. What kind of training do you love — or want to start loving?

Bodyweight & mobility? You’ll need floor space and maybe a mirror.

Strength training? Think squat rack, bench, dumbbells — and solid floors.

Cardio fiend? Make room for a treadmill, rower, or bike.

Stretching, yoga, Pilates? You’ll want calm lighting and warmth.

Write a list of must-have equipment. Are you training solo or sharing the space? Will it double as a home office or studio? Every answer shapes the layout.

Then there’s the budget. Don’t just count the equipment — include the garden room itself, insulation, electrics, flooring, and extras like heating or mirrors. Be realistic. Set your range early and stick to it.

2. Site Selection & Garden Assessment

Not all garden spots are created equal. Look for a spot that ticks these boxes:

Gets natural light, but not direct all-day sun (overheating is real).

Private enough for shirtless squats or loud music.

Accessible for deliveries — you don’t want to haul timber through the house.

Check the ground: Is it level? Does it get soggy in winter? Are there cables or pipes underneath?

The better your site, the smoother your build.

3. Design & Layout

Now for the fun part — shaping your space.

Size matters: Allow enough room to move safely between equipment. A minimum internal space of around 3m x 4m works well for a compact setup.

Ceiling height: Ideally 2.4m+ so you can press overhead and jump without head butting the plasterboard.

Windows & doors: Maximise light and air, but think about privacy and where you’ll place mirrors or wall-mounted gear.

Storage: Hooks for bands, shelves for dumbbells, maybe even a corner cupboard.

Looks: Go for cladding that complements your garden — it should feel like an extension of your home, not an afterthought.

4. Planning Permission & Building Regulations (Crucial!)

Here’s what you need to know about staying legal:

Under Permitted Development, you’re fine if:

Height stays under 2.5m (within 2m of a boundary).
You don’t use more than 50% of your garden.
It’s not forward of your house.
It’s not a full-time living space.

You’ll need Building Regulations if:

The room’s over 30m².
It’s 15–30m² and within 1m of a boundary — fire-rated materials required.
You’re adding electrics — these must comply with Part P.

Want peace of mind? Apply for a Lawful Development Certificate (LDC). It proves you followed the rules. And always, always have a friendly chat with neighbours before breaking ground.

Stage 2: Construction (Building the Shell)

1. Site Preparation & Groundworks

Clear out plants, rocks, or debris. The site must be flat and solid. Use a damp-proof membrane to keep moisture at bay — otherwise your gym becomes a greenhouse for mould.

2. Foundations

There are a few solid options:

Concrete slab: Best for heavy equipment. Long-lasting and rock-solid.

Ground screws: Quicker, no digging, good for uneven ground.

Concrete pads/piers: Great for timber builds — often used with garden room kits.

Whichever you pick, ensure water drains away from the structure.

3. Wall, Floor & Roof Construction

You’ve got three common build types:

Timber frame: Flexible and traditional.

SIPs (Structural Insulated Panels): Fast to assemble, superb insulation.

Log cabin kits: Quicker DIY option but usually need extra insulation.

Don’t skimp on insulation — PIR boards or mineral wool in floor, walls, and roof. Use a vapour control layer to stop sweat and damp creeping into the walls. For roofing, go with a warm roof system if you want true year-round comfort.

Cladding? Composite for low maintenance, timber for charm, render for a modern edge.

4. Windows & Doors

Choose double or triple glazing for comfort and energy savings.

French doors, bifolds, or sliders? That’s down to style and access. Make sure the locks are solid — your gear isn’t cheap.

Stage 3: Electrics, Heating & Ventilation

1. Electrical Installation

This part is not a DIY moment. Get a Part P certified electrician.

You’ll need power from the house — usually via a trench and armoured cable.

Add a separate consumer unit in the gym.

Plan plenty of sockets: treadmill, speakers, phone charger, even a fan.

Good overhead lighting is a must, plus an external light for evening workouts.

2. Heating & Cooling

UK weather is... let’s say, unpredictable.

Winter warmth: Try electric panel heaters, underfloor heating, or infrared panels.

Summer cooling: Consider a portable AC or a fan, but for the best of both worlds, an air source heat pump offers heating and cooling in one.

3. Ventilation

Stale air and sweat aren’t a good combo.

Use openable windows for natural airflow.

Add an extractor fan if the space gets steamy.

Trickle vents offer low-level constant ventilation without opening windows wide.

Stage 4: Internal Fit-Out & Gym Specifics

1. Flooring

Your floor needs to be tough. Think dropped dumbbells, plyo jumps, and heavy machines.

Rubber mats: Great shock absorption and noise reduction.

Heavy-duty vinyl or laminate: Easy to clean and still tough.

Engineered wood: Looks lovely but isn’t forgiving for strength training.

Lay everything securely. No sliding mats allowed.

2. Walls & Ceiling

Keep it stylish but functional.

Plasterboard and paint: Clean and modern.

Timber cladding: Warm and rustic.

Add mirrors for form-checking and to make the space feel bigger.

3. Equipment Installation

Build and place your kit carefully.

Bolt racks or pull-up bars to solid structural points.

Allow space around machines — safety first.

Think about layout flow: cardio at the front, strength in the middle, mobility/stretching at the end.

4. Storage & Organisation

Even the tidiest gym needs clever storage:

Wall hooks for bands and ropes.

Open shelves or cubbies for kettlebells, towels, and sliders.

Maybe even a water cooler or mini fridge — because hydration matters.

Ongoing Maintenance for Your Garden Gym

Regular Checks

Keep it fresh and functional with routine checks:

Outside: Look for rot, cracked cladding, clogged gutters.

Inside: Test sockets, lights, and heating regularly.

Equipment: Clean after use. Check cables, bolts, and moving parts.

A little care goes a long way in keeping your gym feeling brand new.

Conclusion: Invest Time in Planning for Long-Term Gain

Reiterate that a Garden Gym is a Rewarding Project

A garden gym isn’t just a space — it’s a lifestyle upgrade. It’s where you’ll chase progress, manage stress, and maybe even rediscover your love for movement.

Emphasise the Importance of Planning, Regulations, and Quality Construction

Yes, it takes planning. And yes, there are rules. But every hour spent thinking it through saves you hassle (and money) later. From insulation to electrics, quality matters.

Final Thought: With careful planning and attention to detail at each stage, your garden gym will become a comfortable, inspiring, and long-lasting asset for your health and well-being.

Treat it like any big investment — with care, thought, and purpose. Done right, your garden gym will be the best room you’ve ever built.

Ready to Build Your Garden Gym?

We specialise in fully bespoke garden gym room solutions, tailored to your training style, space, and aesthetic. From sourcing top-tier garden room builders to fitting out your gym with premium equipment — we do it all.

📞 Call us on 0330 0430 089
📧 Or email us at support@totalgymstore.co.uk

Let’s create your dream garden gym — together.