Garage Fire Door Requirements: The Door Between House and Garage

What does Approved Document B require for an integral garage?

The legal requirement is Part B of Schedule 1 to the Building Regulations 2010, which applies whenever building work is carried out. The practical guidance for houses sits in Approved Document B Volume 1 (Dwellings). Paragraph 5.6 states that if a garage is attached to or forms an integral part of a dwellinghouse, the garage should be separated from the rest of the dwellinghouse by fire-resisting construction of at least REI 30 — 30 minutes' loadbearing capacity, integrity and insulation, measured from the garage side.

Diagram 5.1 of the same document draws the whole package together. For a house with an integral or attached garage, the guidance expects:

• A separating wall, and any floor between the garage and the house, achieving a minimum fire resistance of REI 30 from the garage side.
• Any connecting fire door achieving a minimum fire resistance of E30 Sa — 30 minutes' integrity plus cold smoke control — and fitted with a self-closing device.
• A door threshold at least 100mm above the garage floor, or a garage floor laid to fall away from the door towards the outside.

The logic is simple: garages hold cars, fuel, and often the household's most ignitable clutter, so the guidance treats the garage as a higher-risk space and puts a 30-minute fire-resisting envelope between it and the rooms where people sleep. Approved Document B is statutory guidance rather than the law itself — you can propose an alternative way of meeting Part B — but for a standard house the Diagram 5.1 arrangement is what building control bodies expect to see.

What rating does the door between house and garage need?

Table C1 of Approved Document B Volume 1 lists the door "between a dwellinghouse and a garage" and gives it the highest rating of any door position inside a house: E30 Sa under the European classification (BS EN 13501-2, tested to BS EN 1634-1), or FD30S under the historic BS 476-22 route. The "Sa" and "S" suffixes both mean the doorset must also restrict cold smoke, not just fire.

Two details are worth pinning down. First, E30 is an integrity-only rating: the door holds back flames and hot gases for 30 minutes but is not required to insulate against heat transfer, so E30 is not the same as EI30 — see our guide to BS 476 vs EN 1634 testing. Second, the smoke condition has teeth: Table C1's notes require either the Sa classification to BS EN 1634-3 or a leakage rate of no more than 3m³ per metre of door edge per hour (head and jambs) when tested at 25Pa. In practice that means a doorset with fitted smoke seals, usually combined with intumescent strips in the same carrier.

The BS 476 column is on borrowed time. The 2029 amendment to Approved Document B removes the national classes with effect from 2 September 2029, after which new work is specified against the European standard only. If you are buying a doorset now, evidence to BS EN 1634-1 with an Sa smoke rating is the future-proof choice — our FD30 vs FD60 guide explains how the designations map onto each other.

Does a garage fire door need a self-closer?

Yes — and this is the single most confused point in the whole topic. Appendix C, paragraph C5 of Approved Document B Volume 1 says: "All fire doorsets, including to flat entrances and between a dwellinghouse and an integral garage, should be fitted with a self-closing device", and then lists the exceptions — fire doorsets to cupboards, to service ducts normally locked shut, and fire doorsets within flats and dwellinghouses.

That last exception is where the confusion comes from. Most fire doors inside a house — for example the doors protecting the stairway in a loft-converted home — do not need self-closers under current guidance. The house-to-garage door is the deliberate exception: it is named in paragraph C5 as requiring a closer, and Diagram 5.1 repeats the requirement. People who remember the general dwelling exemption often assume it covers the garage door too. It does not.

For the closer itself, specify a device tested to BS EN 1154 and included in the doorset's fire test evidence, adjusted so the door closes fully into its latch from any opening angle. Rising-butt hinges are generally a poor substitute because they struggle to overcome latch resistance and seals on the final few degrees of closing.

Do you need a step down into the garage?

Not necessarily — and this provision is often misquoted as an absolute rule. Paragraph 5.7 of Approved Document B Volume 1 says that where a door is provided between the house and the garage, it should meet one of two conditions:

1. The garage floor is laid so that it falls away from the door towards the outside, allowing fuel spills to flow away from the house; or
2. The door opening is a minimum of 100mm above the level of the garage floor.

The purpose is petrol: a fuel spill on the garage floor should drain towards the main vehicle door, not pool against — or seep under — the door into the hallway. It is one or the other, not both. Many modern designs use the laid-to-fall option precisely because a 100mm step conflicts with level-access ambitions elsewhere in the design. LABC Warranty's technical guidance for garages likewise recommends laying garage floors to falls or providing a suitable step so that liquid disperses away from the building.

Be honest with yourself about what this means for an existing house: if your integral garage floor is dead level with the hallway and slopes nowhere, the spillage provision is not met as built. That is worth fixing when you next do work to the garage, even though there is no obligation to act retrospectively.

Walls, ceilings and rooms above the garage

The fire door is only one part of a 30-minute enclosure, and it is the part most often fitted while the rest is forgotten. Diagram 5.1 applies the REI 30 standard to the separating wall and any floor between the garage and the dwellinghouse — so if there is a bedroom or landing above an integral garage, the garage ceiling build-up must deliver 30 minutes' fire resistance from below, not just the wall beside the door.

• Separating wall: masonry or a fire-rated stud build-up achieving REI 30 from the garage side, taken up to the underside of the fire-resisting ceiling or roof line with junctions fire-stopped.
• Ceiling below habitable rooms: a build-up with test evidence for 30 minutes from the exposed (garage) face; downlighters and loft hatches in that ceiling need fire-rated versions.
• Service penetrations: pipes, cables and boiler flues passing through the separating construction should be fire-stopped with appropriate sealing systems.
• The doorset: E30 Sa (FD30S) with smoke seals and a self-closer, as above.

The exact wall and ceiling build-ups are a matter for your designer and building control body, because they depend on tested systems rather than a single recipe. The point to hold onto is that a certificated fire door hung in a wall full of unsealed holes does not create 30 minutes of separation.

When do the rules apply — and is an existing garage exempt?

Building Regulations apply to building work, defined in regulation 3 of the Building Regulations 2010 to include erecting or extending a building and making a material alteration — work that would leave the building less compliant with a relevant requirement, or more unsatisfactory in relation to one, than before. They are not retrospective. If your 1975 house was compliant with the rules in force when it was built, nobody can require you to upgrade the garage door simply because guidance has moved on, and there is no statutory fire door inspection when you sell a private house.

The current standards bite when you do work. The common triggers are:

• Building a new house or an integral garage: the full Diagram 5.1 package applies.
• Converting the garage to habitable space: the Planning Portal confirms that converting a garage, or part of one, into habitable space will normally require building regulations approval — and if part of the garage remains a garage, the new separation between it and the converted room needs to meet current guidance.
• Extending over the garage: creating a room above brings the REI 30 floor requirement and the doorset provisions into play.
• Replacing or altering the door or the separating wall: swapping an existing fire door for an ordinary hollow-core door makes the building more unsatisfactory in relation to Part B — the definition of a material alteration — so replacement should be like-for-like or better.

When you sell, unauthorised alterations tend to surface anyway: conveyancers routinely ask for building control completion certificates for garage conversions and extensions, and a missing certificate can delay a sale or trigger an indemnity-policy negotiation. Note also that paragraphs 5.6 and 5.7 apply to garages *attached to or forming an integral part of* the house — a detached garage across the driveway is not covered by these separation provisions, though other parts of the regulations may still apply to building one.

What does a compliant house-to-garage doorset look like?

Pulling the verified requirements together, here is the practical specification we would look for on a house-to-garage door in England today:

• A third-party certificated doorset rated E30 Sa to BS EN 1634-1 (sold as FD30S under the older designation), typically a 44mm leaf, supplied with its certification label or plug intact — see how to identify a fire door.
• Intumescent strips and cold smoke seals to the head and jambs, matching the tested configuration — never painted over or trimmed out.
• A self-closing device to BS EN 1154, covered by the doorset's test evidence and adjusted to close the door fully into the latch.
• Perimeter gaps of 2–4mm at head and jambs in line with BS 8214 installation practice, with the threshold gap kept within the doorset manufacturer's smoke-control tolerance — our gap tolerances guide covers the numbers.
• Hinges, latch and hardware that are CE/UKCA-marked and compatible with the fire certification.
• Installation following the manufacturer's instructions, ideally by an installer under a recognised competency scheme — see who can install fire doors.
• A threshold arrangement that respects paragraph 5.7: either the 100mm step up into the house or a garage floor laid to fall towards the vehicle door.

Once fitted, the door earns its keep only if it stays in working order. A quick periodic check — closes fully from any angle, seals continuous, gaps in tolerance, closer not disconnected — takes minutes; our free fire door inspection checklist walks through it.