Log Burner in a Garden Room — UK 2026 Cost Guide
Garden offices, summerhouses, and dedicated outbuildings are the subject of different building and notification systems across the UK. Indicative professional cost: £3,300–£5,300, with the flue route and nearby buildings among the main variables.
The short answer
UK 2026 typical: £3,300–£5,300 total installed for a log burner in a garden room or detached outbuilding. The position of the flue outlet relative to its own roof, nearby openings and an adjacent building can require a taller route.
A compliant installation can be feasible, but it is not automatically permitted. England and Wales publish separate Approved Documents J; Scotland and Northern Ireland use different building-standard systems. Planning, listed-building, lease and site-use constraints must be checked separately.
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 calculatorWhat 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.
- Installation and notification labour: depends on the national approval route, penetrations, fire-stopping and whether the installer can specify positions before construction
The 2.3m adjacent-building check
England’s Approved Document J Diagram 17 says that, where the flue outlet is within 2.3 metres horizontally of an adjoining or adjacent building, it should be at least 600mm above every part of that building within the same distance. The normal clearances from the outbuilding roof and nearby openings also apply.
This is a measurement from the proposed outlet, not a blanket rule based only on the gap between two buildings. It can require a much taller flue beside a two-storey house, but the extra length and cost must be designed from the actual geometry. Wales has its own Approved Document J; use the Scottish or Northern Irish guidance for work there.
Flue height and powered draught
English and Welsh guidance commonly starts with a 4.5m minimum flue height measured from the appliance outlet, while the appliance and flue manufacturer can require more. A low outbuilding does not remove that design requirement.
Do not treat a powered fan as a generic shortcut for a short flue. Any mechanical draught system must be compatible with the exact appliance and designed so a failure cannot spill combustion gases. This needs manufacturer and competent specialist approval, as do any departures from the normal height guidance.
Building requirements still apply
The figures below are common English and Welsh guidance points, not a single UK rulebook. Confirm the current national document, appliance instructions and site design before construction.
- Hearth ≥840×840mm, non-combustible, ≥150mm beyond stove sides, ≥300mm in front of door
- A suitable carbon-monoxide alarm positioned under the applicable national guidance and manufacturer instructions
- 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
In England and Wales, an appropriately registered HETAS business may be able to self-certify eligible work; otherwise use building control. Scotland uses the local-authority building-standards route, and Northern Ireland uses district-council building control.
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 installerFrequently asked questions
Can I install a log burner in a garden room?
Potentially, subject to the building’s use and location. England and Wales use their separate Approved Documents J; Scotland uses its Technical Handbook and Northern Ireland uses Technical Booklet L. Confirm both planning and building-control requirements before work starts; a twin-wall flue is usually needed where there is no masonry chimney.
How much does a garden-room log burner install cost?
This guide's indicative UK 2026 range is £3,300–£5,300. A single-storey structure can simplify the route, but it does not remove minimum flue-height, roof, opening or adjacent-building clearance checks. Price the actual flue design rather than the building height alone.
What is the 2.3m adjacent-building check?
In England, if the proposed outlet is within 2.3m horizontally of an adjacent building, Approved Document J says it should be at least 600mm above every part of that building within the distance. This is measured from the outlet and can lengthen a flue, but it is not a blanket main-roof-height rule. Other UK nations publish separate guidance.
Will the flue work without 4.5 metres of height?
English and Welsh guidance commonly starts with 4.5m from the appliance outlet, and the manufacturer can require more. Do not add a generic powered fan as a shortcut: any mechanical draught system must be compatible with the appliance and designed by a competent specialist so a failure cannot spill combustion gases.
Do I need a CO alarm in a garden room with a stove?
A suitable BS EN 50291 CO alarm should be provided with a new fixed stove. The source is separate Approved Documents J in England and Wales, Scotland’s Technical Handbook, or Northern Irish Technical Booklet L. Follow the applicable national guidance and the alarm manufacturer’s instructions.