For all residential properties
Updated: 03/23/2026

Here are the common standards and requirements for residential basements based on ceiling height and floor slope. Not all building standards that apply to basements are covered here; refer to the adopted building codes for comprehensive information.

For remodeling a basement to a habitable space, see the plan requirements at Additions & Remodels.

DEFINITIONS 

A basement is a floor level below the first story in a building that meets a height standard:

  • If floor-to-ceiling height is at least 6'8" - The space is considered a basement.
  • If floor-to-ceiling height is less than 6'8" - The space is considered an under-floor area or crawl space. 
  • If floor-to-ceiling height is 6'8" minimum but the floor slopes more than 2 percent due to hillside topography, the area may be considered an under-floor area due to its non-usability.

Habitable basement minimum ceiling height - 7' is the minimum ceiling height for a habitable basement. Other code requirements apply to a habitable basement.

Non-habitable basement - If not intended as habitable space, then the basement must be maintained as follows:

  • Cannot be finished to look like a habitable space.
  • Lighting must be limited to minor general lighting and for servicing any permanently installed HVAC equipment. 

Basement Requirements

Access, Exits & Escape Routes
Window Well or Light Well
Landings
Guardrails
Drainage
Security Bars, Grilles, Grates & Covers

Underfloor Area / Crawl Space Requirements

Limited Allowable Uses
Access, Exits & Escape Routes

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