Door Clearances and Fire Door Installation
10 mm
Internal doors, including fire doors, must be installed with sufficient clearance from the finished floor level to accommodate flooring, typically around 10mm for non-fire doors
Every figure for this topic is on one page: Cavity barriers and fire stopping around openings and services
Read the full answerInternal doors, including fire doors, must be installed with sufficient clearance from the finished floor level to accommodate flooring, typically around 10mm for non-fire doors. Fire doors require precise gaps around their perimeter, usually 3mm-4mm, to ensure their integrity during a fire, and must always be installed according to the manufacturer's instructions and tested specifications.
Basis in regulation
BS 8214
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How to check it on site
Check that door clearances are adequate for floor coverings and fire door gaps are within specified tolerances and installed correctly.
Common failure
Insufficient clearance under doors can prevent carpet installation, while incorrect gaps around fire doors compromise their fire resistance.
Last updated 23 August 2026. This is our editorial summary of publicly available regulation, not building control approval or a warranty determination.