What Is a Fire Door?
A fire door is a door constructed and fitted to resist the passage of fire and smoke for a specified period — typically 30 minutes (FD30) or 60 minutes (FD60). Fire doors must:
- Be made of fire-resisting material to the specified performance standard
- Be fitted with an intumescent strip that expands when heated, sealing the door edge
- Be fitted with a smoke seal (cold smoke seal) around the frame
- Be fitted with a self-closing device (door closer) so they close automatically after opening
- Be installed in a fire-resisting frame
A door marked FD30 provides 30 minutes of fire resistance. Fire doors without a closer fail the performance standard — a propped-open fire door is no fire door at all.
When Are Fire Doors Required Under Building Regulations?
Loft Conversions (Most Common Requirement)
When a loft conversion is added to a two-storey house, the existing staircase becomes the means of escape for the new loft floor. Building Regulations (Approved Document B, Fire Safety) typically require:
- FD30S fire doors (FD30 with smoke seals) to be fitted to all habitable rooms that open onto the staircase enclosure on the first and ground floors
- The staircase is enclosed from the loft level to the ground-floor exit
This means that in a typical Victorian terrace where the staircase is open to the landing, fitting a loft conversion requires enclosing the staircase with fire-resisting construction and fitting FD30S doors to all rooms opening onto it.
Practical implication: Adding a loft conversion often requires replacing existing bedroom and living room doors with FD30S fire doors — an often-overlooked cost and disruption during loft conversion works.
HMO and Multi-Occupancy Properties
Houses in Multiple Occupation (HMOs) require fire doors throughout under the Housing Act 2004 and associated licensing conditions. Typically:
- FD30S to all bedroom and kitchen doors
- FD30S to all doors opening onto the means of escape routes
- Fire doors with closers throughout common areas
HMO fire safety requirements are set by the local authority licensing authority and may be more stringent than the minimum Building Regulations standard.
Three-Storey or Taller Houses
In a three-storey (or taller) house with a single staircase, fire doors are required to all rooms opening onto the staircase enclosure under Approved Document B.
Where Fire Doors Are NOT Required
In a standard two-storey house without a loft conversion, fire doors are not required under Building Regulations (though they are recommended and some insurers incentivise them). A house with only two habitable floors and an unenclosed staircase does not need fire doors under current regulations.
Common Fire Door Misunderstandings
- "Any solid door will do": A solid-core door without intumescent strip, smoke seals, and a closer is not a fire door
- "The door doesn't need to be self-closing": A fire door without a self-closer does not meet the specification — it must close automatically
- "Existing hollow-core doors can be upgraded": Generally, hollow-core doors cannot be upgraded to fire-door standard — they must be replaced
- "We can prop fire doors open": A fire door that is propped open provides no protection
Certification
Fire doors should be:
- Certified by the manufacturer to BS 476: Part 22 or EN 1634-1
- Identified by a label on the top rail confirming the fire performance (FD30 or FD60)
- Installed strictly in accordance with the manufacturer's instructions (including door gap tolerances)
RCB Design & Build
RCB identifies fire door requirements at the pre-construction stage for all loft conversion, HMO, and multi-storey refurbishment projects, ensuring that compliance costs are included in the scope from the outset.