Guide — Home Fire Safety
Fire Risk in Rented Outbuildings
Garages, sheds, and garden studios are consistently identified in fire incident data as sites of uncontrolled fire starts that spread to the main dwelling. Their combination of fuel storage, electrical installations, and low occupancy makes them higher-risk than most rooms in the house.
Key insight
An outbuilding fire that is not detected within the first few minutes can become a structure fire affecting the main dwelling before the occupants are even aware of it — especially overnight. Fitting a smoke alarm inside the outbuilding and ensuring it is interlinked to alarms in the main house eliminates this blind spot.
Outbuilding hazards and mitigations
| Hazard | Risk level | Mitigation |
|---|---|---|
| Petrol storage | Very High | Maximum 30 litres in approved metal containers; store in ventilated space away from ignition sources; never store inside the main building |
| LPG cylinders | Very High | Store upright outside or in ventilated outbuilding; away from drains and basement access; never inside a garage with vehicles |
| Lithium battery charging | High | Never charge unattended overnight; use manufacturer-specified charger; charge on hard non-combustible surface; fit a smoke alarm |
| Electrical wiring | High | All outbuilding electrical installations must be certified under Part P Building Regulations; EICR every 5 years |
| Solvent and paint storage | Medium–High | Store in locked metal cabinet; limit quantities; no open flames in same space |
| Combustible clutter | Medium | Do not store cardboard, paper, or foam in proximity to heat sources; maintain clear access to any emergency exits |
Attached vs detached: why proximity matters
An attached garage shares a wall with the main house. A fire in an attached garage has a direct fire spread path into the living space if the connecting door is not an FD30 fire door. Check this door carefully — many attached garages have standard hollow-core doors installed, which provide minimal fire resistance. For fire door standards, see our fire door safety guide.
A detached outbuilding within 3 metres of the main structure can spread fire through radiated heat and flying brands. Keep the gap between outbuildings and the main dwelling as large as practical, and ensure no combustible materials are stored against the main building wall.
Electrical installations in outbuildings
Any fixed electrical installation in an outbuilding — lighting, sockets, EV charger — must comply with Part P of the Building Regulations and be certified by a competent electrician. An uncertified or DIY outbuilding electrical installation is a leading cause of garage and shed fires. Request an Electrical Installation Condition Report (EICR) on any older outbuilding installation. For broader guidance, see our electrical fire prevention guide and our garage fire risks article.
Frequently asked questions
FAQ