CodeMandatory
Habitable room minimum area
CM-ROOM-AREA-01Description
Every habitable room must have at least 70 sq ft of floor area, with no horizontal dimension less than 7 ft.
Why this exists
Habitable rooms must be large enough to function — IRC sets 70 sq ft minimum and 7 ft minimum on any horizontal dimension to prevent unusable closet-sized 'bedrooms'.
Categories
Life safetyBedroom
Source
ICCno manifest entry
International Residential Code (2024)
Section: R304.1
Published 2026-05-09 · last verified 2026-05-09
Solver enforcement
The constraint solver runs check function cm-room-area-01 as a hard constraint — layouts that fail are rejected outright.
Backed by research
Habitable rooms must be at least 70 sq ft, with no horizontal dimension less than 7 ft.
Council (2024), ICC — R304.1 — view source ↗
See the full research bibliography for context. Our licensing principle describes how we cite published research without using the underlying datasets.
Related directives
- Garage / dwelling fire separation · IRC R302.6
- Habitable space minimum ceiling height · IRC R305.1
- Egress window net opening dimensions · IRC R310.2
- Stair riser, tread, and headroom · IRC R311.7
- Smoke alarms required throughout dwelling · IRC R314
Last reviewed 2026-05-09.