Log Burner in a Garden Room — UK 2026 Cost Guide
Garden offices, summerhouses, and dedicated outbuildings are the fastest-growing UK install scenario. Total cost £3,300–£5,300 — once you understand the 2.3m rule, the price predicts itself.
The short answer
UK 2026 typical: £3,300–£5,300 total installed for a log burner in a garden room or detached outbuilding. The big variable is proximity to the main house — within 2.3 metres you face the proximity rule (see below) which can push totals up by £800–£2,000.
Garden installs are entirely feasible and legal — Approved Document J and BS8303:2018 apply just as they do inside the main house. No planning permission needed in most cases unless the property is listed.
Get your garden-room install estimate
Pick "Garden room / outbuilding" on step 5. The calculator factors in the single-storey flue advantage and the standard scenario uplift.
Open the calculator →What you're paying for
- Twin-wall flue system: garden rooms don't have masonry chimneys, so a twin-wall insulated flue is required. Single-storey runs are short (1.5–3m vs 5–7m for a two-storey house), keeping costs lower. £900–£1,800 installed.
- Stove unit: typically £500–£2,500. Small Ecodesign stoves (4–5kW) are well-matched to garden room volumes.
- Hearth + register/floor plate: £300–£700 combined. Constructional hearth may be needed if the garden room floor is combustible timber.
- HETAS labour: 1 day single-storey, slightly less if the building is brand new and the installer can specify exact positions in advance.
The 2.3m proximity rule
If your garden building is within 2.3 metres of the main house, the flue must terminate at the height of the main house roof — not just the garden building roof. This is to prevent smoke from a low outbuilding affecting the main dwelling.
In practice this can mean an additional 4–6 metres of twin-wall pipe at £60–£120 per metre, raising the flue element by £800–£2,000. If you have the option, siting the garden building 2.3m+ from the main house is the simplest way to keep costs at the lower end.
Flue height and powered draught
Natural draught typically needs the flue to reach 4.5 metres above the stove. In low-height garden buildings — a single 8'-tall summerhouse, say — that can be tricky to achieve with internal flue alone.
A powered flue fan(£150–£300 for the device, battery or mains-powered) assists draught when the flue is shorter than 4.5m. Salamander Stoves and other UK suppliers sell garden-room-specific kits with appropriate fans included. Note that if the building is within 2.3m of the house, the proximity rule overrides — you'll need full height anyway.
Building Regulations apply just as much
- Hearth ≥840×840mm, non-combustible, ≥150mm beyond stove sides, ≥300mm in front of door
- CO alarm in the building — battery-only (BS EN 50291) is fully compliant
- Permanent air vent for stoves above 5kW or in airtight builds
- Fire-rated wall boarding behind and beside the stove if combustible timber is present
- Flue clearance ≥3× diameter from combustibles for single-skin pipe
HETAS-registered installer is strongly recommended — the Building Regulations notification process is identical to a main-house install. Outdoor kitchens and pure outdoor stove installations (not in an enclosed structure) are outside HETAS scope.
Recommended garden-room stoves
Small Ecodesign stoves (3–5kW) match typical garden room volumes. Going smaller than your room needs is the right move — overheating a confined glass-fronted garden building is the #1 recurring owner complaint.
- Salamander Hobbit(~£449, 3.5kW) — designed specifically for compact spaces like garden rooms and shepherd's huts.
- Charnwood Country 4 BLU (£994, 4kW) — best UK-made entry. Single-lever Quattroflow. Charnwood guide →
- Aarrow Hamlet Solution 4 (£695, 4.5kW multifuel) — budget entry point. Aarrow guide →
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Find an installer →Frequently asked questions
Can I install a log burner in a garden room?
Yes. Garden rooms, garden offices, and summerhouses can host a log burner provided they comply with Approved Document J and BS8303:2018. No planning permission needed unless the property is listed. A twin-wall flue is essentially always required since garden buildings don't have masonry chimneys.
How much does a garden-room log burner install cost?
UK 2026: £3,300–£5,300 total installed for a typical setup. Single-storey building keeps the flue short (1.5–3m vs 5–7m for a two-storey house). The biggest cost variable is whether you're within 2.3m of the main house.
What's the 2.3m rule and why does it matter?
If your garden building is within 2.3 metres of the main house, the flue must terminate at the height of the main house roof — not the garden building roof. That can add 4–6 metres of additional twin-wall pipe at £60–£120 per metre, raising the flue element by £800–£2,000.
Will the flue work without 4.5 metres of height?
Natural draught typically needs 4.5m+. In low-height garden buildings, a powered flue fan (£150–£300 for the device, battery or mains-powered) assists draught. If the building is within 2.3m of the house, the proximity rule overrides — you'll need the full height anyway.
Do I need a CO alarm in a garden room with a stove?
Yes — mandatory under Approved Document J. A battery-only CO alarm (BS EN 50291) is fully compliant; you don't need mains power. Place at least 300mm from any wall, between 1m and 3m from the stove.