Search the building code.

• IBC 506.3

  Frontage increase

  • A building must adjoin or reach a public way to get the frontage area increase per 506.3.1 to 506.3.3.

  International Building Code, 2024 · Chapter 5, General Building Heights and AreasRead the full text (opens UpCodes in a new tab)

• IBC 506.3.1

  Minimum percentage of perimeter

  • At least 25% of the perimeter must face a public way or open space reached from a street or fire lane.

  International Building Code, 2024 · Chapter 5, General Building Heights and AreasRead the full text (opens UpCodes in a new tab)

• IBC 506.3.2

  Minimum frontage distance

  • The open space must be at least 20 ft wide, measured from the building to the nearest interior lot line, across the full street, or to another building on the lot; use the narrowest qualifying width.

  International Building Code, 2024 · Chapter 5, General Building Heights and AreasRead the full text (opens UpCodes in a new tab)

• IBC 506.3.3

  Amount of increase

  • Frontage increase If from Table 506.3.3: by % of perimeter (25–50, 50–75, 75–100) and open space width (20–25, 25–30, 30+ ft): 0.17/0.21/0.25, 0.33/0.42/0.50, 0.50/0.63/0.75; interpolation allowed.

  International Building Code, 2024 · Chapter 5, General Building Heights and AreasRead the full text (opens UpCodes in a new tab)

• IBC 506.3.3.1

  Section 507 buildings

  • A Section 507 building short of its 60-ft yards uses Table 506.3.3.1 with open space of 30 ft or more; If up to 1.50 at 75–100% perimeter and 55 ft.

  International Building Code, 2024 · Chapter 5, General Building Heights and AreasRead the full text (opens UpCodes in a new tab)

• IBC 506.2

  Allowable area determination

  • Allowable area comes from 506.2.1, 506.2.2 and the frontage increase in 506.3, using Table 506.2 factors.
  • Unsprinklered (NS) factors, e.g. VB: B 9,000, M 9,000, A-2/A-3 6,000, E 9,500, R-1/R-2/R-4 7,000, S-1 9,000, U 5,500; R-3 is unlimited. For these groups the sprinklered one-story factor (S1) is 4 × NS and multistory (SM) is 3 × NS.

  Works withIBC 506.2.1IBC 506.2.2IBC 506.3

  International Building Code, 2024 · Chapter 5, General Building Heights and AreasRead the full text (opens UpCodes in a new tab)

Searches all 4,276 IRC 2024 sections, 5,532 IBC 2024 sections and defined terms (Chapters 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33 so far) and each city's local rules as they are added. Section numbers and titles from the International Residential Code and International Building Code, 2024 editions, copyrighted by the International Code Council; the IRC's electrical chapters (34 to 43) follow NFPA 70, the National Electrical Code. Requirements are summarized in our words (IRC Chapters 3 to 43, IBC Chapters 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33); read the full text at the link on each result. Local values come from each city's published documents.