There is a lot of confident, contradictory advice about this online, some of it from people selling fire doors. What follows is our reading of the guidance for England and Wales. It is not a substitute for your building control officer, who has the final word and should be asked early.
The short version
In a two storey house with no loft conversion, you almost certainly need no fire doors at all, with one common exception: a door between an integral garage and the house.
Once a house has three storeys, or a habitable room in the roof, the staircase becomes a protected escape route and every habitable room opening onto it needs an FD30 door with intumescent strips.
What counts as a storey
A converted loft with a proper staircase counts. A loft with a fixed ladder generally does not, because it is not a habitable room in the regulatory sense, though it may still need one for insurance.
A basement counts, and this catches people out on London terraces where the lower ground floor was dug out years ago and nobody thought of it as a storey.
What an FD30 door has to be
The rating belongs to the doorset, not the leaf. A certified door hung in a lining without the right strips, with the wrong hinges, or with a 12mm gap at the head, is not a fire door however good the certificate looks.
- Three hinges, CE marked, fitted with the screws supplied.
- Intumescent strips in the leaf or the lining, continuous on all four edges.
- A gap of 2mm to 4mm around the leaf, and no more than 10mm at the threshold.
- A self-closer where the door opens onto the escape stair from a garage or a loft room.
Where people over-specify
Bathrooms and en-suites do not need fire doors. Neither do cupboards, unless the cupboard houses a boiler and opens onto the stair. Fitting FD30 throughout a two storey house is a common and expensive piece of belt-and-braces that buys you nothing you can point to.
If you are unsure, our answer is always the same: ask building control before you order, not after. We will hold an order for a fortnight while you do.
Still unsure? Send a photograph of the opening with your question.
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