If you're undertaking a substantial extension, renovation or conversion, your architect will specify if they're required. However, fire doors are essential in the following circumstances:
* If you have a door leading from a garage to the main house in a two-storey build.
* If you are building or renovating a home with three or more storeys (including loft conversion). In this case every room off the stairwells must have fire doors. To be sure, always ask your architect for advice.