Door clearance (also known as a margin or gap) is the small dimensional difference between the inside of a door frame and the size of the moving door leaf or window sash, needed for free movement and assembly. Without clearance, a door would jam or fail to close when the wood expands.
Why it is needed
Wood and other materials move: they swell with moisture and shrink when dry. Some clearance is also needed for installation tolerances:
- Timber movement — a wooden door expands seasonally
- Installation tolerances — a frame is never perfectly square
- Hardware — hinges and latches must operate freely
- Sealing — room for weather strips or draft seals
Common dimensions
For interior doors typical standards are:
- Top — 3 mm clearance between door edge and head jamb
- Sides — 2 to 3 mm at each side jamb
- Bottom — 5 to 10 mm clearance for floor finishes and air circulation
- With underfloor heating — sometimes up to 15 mm for return airflow
For exterior doors the side clearance is usually smaller (1 to 2 mm), since a weather strip or rubber seal fills the g
ap.
Applications
Door clearance plays a role in:
- Doors and windows — fitting moving parts in a frame
- Shutters and panels — free movement between fixed parts
- Sliding doors — clearance top and bottom for sliding
- Built-in cabinetry — fit of fronts in a casework opening
Points to consider
- Too tight — a door that jams in summer was usually hung too tightly
- Too loose — large gaps allow drafts and sound transfer
- Uneven — irregular clearance is visually obvious
- Floor finishes — allow for later parquet or tile
Related terms
- Door frame
- Rebate
- Stop
- Reveal
- Hardware
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