What the ratings mean
Fire doors are rated by how long they are designed to resist fire in tests. FD20 (also written E20) means 20 minutes; FD30 (E30) means 30 minutes. An “S” (for example FD30S) means the door also has smoke seals. The rating applies to the complete door set: door, frame, hinges, seals and gaps, not just the door leaf.
Loft conversions and three-storey homes
When a loft conversion turns a two-storey house into three storeys, the usual approach is a protected stairway from the top floor down to an exit. That typically means fire-resisting doors onto the stairs on every level, along with fire-resisting partitions and interlinked smoke alarms. Existing doors may need upgrading or replacing. Your Building Control body will confirm what your layout needs. See Building Regulations for extensions and lofts.
Integral and attached garages
A door between a house and an integral garage is normally expected to be a self-closing fire door with smoke seals, because garages hold fuel and vehicles. Most other fire doors inside a single house do not need self-closers, but this one does. Check with Building Control if you are converting a garage or adding a new connecting door.
Flats
- Flat front doors that open onto shared corridors or stairs are usually fire doors and play a key part in the building’s fire safety.
- In England, in blocks with storeys over 11 metres, the responsible person (often the building owner or managing agent) must check communal fire doors every three months and make best-endeavour annual checks of flat entrance doors.
- Do not change or replace a flat front door without checking with the freeholder or managing agent first.
Fitting matters
- Fire doors should be installed in line with the manufacturer’s instructions, with the right frame, hinges, intumescent seals and gaps.
- Do not cut down a fire door, add letterboxes or glazing, or swap the hardware without checking it is compatible with the certification.
- Never wedge self-closing fire doors open.
Use a carpenter or joiner experienced in fitting certified fire door sets, and ask for the door’s certification details.
Wales, Scotland and Northern Ireland have their own building rules. This guide covers England; elsewhere in the UK, check with your local council.
Last updated: 14 October 2026
