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Home / Code Guides / Building Address Numbers

Building Address Number Requirements — IFC 505.1

Address numbers are a fire access item: responders have to find the building fast, day or night. The model fire code gives a short rule on size and visibility, and fire districts regularly make it stricter with larger numbers, lighting, or a second location on private roads.

RequirementModel Code StandardSection
Where requiredNew and existing buildings must have approved address numbers or lettersIFC 505.1
VisibilityPlaced so they are plainly legible and visible from the street or road fronting the propertyIFC 505.1
Minimum sizeArabic numerals or letters at least 4 in. high with a stroke width of at least 0.5 in.IFC 505.1
ContrastCharacters must contrast with their backgroundIFC 505.1
MaintenanceNumbers must be kept in place and legible, not covered by landscaping, signs or later constructionIFC 505.1
Buildings not visible from the streetWhere a building sits back or is reached by a private road, the fire code official may require numbers at the road entrance or additional locations, such as a monument or post, so the structure can still be identifiedIFC 505.1

Worth knowing

  • 4 in. is the model-code minimum, not the usual local requirement. Many fire districts require 6 to 12 in. depending on how far the building sits from the street, and some require the numbers to be lit. Always check your local fire code.
  • Reflective or illuminated numbers are a frequent local add-on for new construction; the base IFC text above does not require lighting.
  • Putting the number only on a door or a mailbox far from the building often fails: the test is whether it is visible from the street at the building.
  • Address numbers are separate from the fire-department-access and fire-lane signs in the rest of IFC Chapter 5.

Common questions

What does the code say about where required for Building Address Numbers?

New and existing buildings must have approved address numbers or letters. (IFC 505.1)

What does the code say about visibility for Building Address Numbers?

Placed so they are plainly legible and visible from the street or road fronting the property. (IFC 505.1)

What does the code say about minimum size for Building Address Numbers?

Arabic numerals or letters at least 4 in. high with a stroke width of at least 0.5 in.. (IFC 505.1)

Adopted edition by state

Base-code year from BuildSpec’s adoption records. States often amend the base code, and your city or county may differ, so confirm with your building department. Fire codes are usually adopted by the state fire marshal or the local fire district; BuildSpec holds an IFC edition on record for only the states listed here.

This guide is BuildSpec’s own summary, not code text. It cites the International Fire Code (IFC) as a model standard, and NFPA 10 where a rule is cited to it; BuildSpec publishes no NFPA text, which is at nfpa.org. The IFC itself is available from the ICC. Neither is an adoption record: your state may be on a different edition with amendments — check your jurisdiction page or get an Address Report.
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