Boise, ID Building Setbacks & Zoning: Structure Height Limits (2026)
Key Facts
- R-1A / R-1B max height
- 35 ft.
- R-1C max height
- 3 stories, 40 ft.
- R-2 max height
- 4 stories, 45 ft.
- R-3 max height
- 4 stories, 50 ft.
- Height measured
- grade to highest roof point
- Rooftop solar exception
- up to 18 in. above limit
- Ham/TV antenna exception
- 45 ft., rear yard only
Summary
Boise's Development Code sets a flat 35-foot cap on new houses in the R-1A and R-1B districts, rising to 40 feet (3 stories) in R-1C, 45 feet (4 stories) in R-2, and 50 feet (4 stories) in R-3. Height is measured as the vertical distance from grade to the highest point of the roof, with narrow, listed exceptions for rooftop equipment and antennas.
TABLE 11-02.3: R-1A LOT AND BUILDING STANDARDS ... HEIGHT (MAXIMUM) D Building Height 35 ft. ... 4. Height: A. Building Height: (1) The vertical distance from the grade to the highest point of the roof or structure that is not listed as an exception to the maximum building height limits in Section 11-04-03.3.C. (2) Towers, steeples, spires, belfries, cupolas, and domes on primary nonresidential structures, provided they are not used for human occupancy, are exempt from building height limits if their largest horizontal cross-section does not exceed 20 percent of the horizontal cross-section of the top floor ceiling plate of the building. ... C. Permitted Exceptions Through Building Height Limits: Certain building and site features listed in Table 11-04.5 below may exceed the maximum building height limits listed in Section 11-04-03.2, Dimensional Standards Summary Tables
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 S-31: Code current through: Ord. 20-26, passed 6-9-2026).
Full Breakdown
5 for R-1B. " Complete dimensional standards, including these height caps, are cross-referenced to Section 11-04-03, Lot and Building Design and Dimensions. C," and separately exempts towers, steeples, spires, belfries, cupolas, and domes on primary nonresidential structures from the height limit if they are not used for human occupancy and their horizontal cross-section does not exceed 20 percent of the top floor ceiling plate. 5 list the features allowed to exceed the district height cap: accessory rooftop solar collectors may extend up to 18 inches above the limit, an accessory wind energy system may reach 10 feet above the limit for primary structures, chimneys, ventilators, skylights, water tanks, bulkheads and similar roof-mounted mechanical appurtenances are exempt outright, and a ham radio or television antenna may reach 45 feet from finished grade but only in the rear yard and only if it meets all required setbacks.
D(2) tightens the standard rule: if an existing dwelling of less than two stories abuts either side of the lot, the new building's height is capped at 35 feet and two stories, excluding basements, even in a district that would otherwise allow more.
Violations & Fines
Height compliance is checked during the City's plan review and building permit process, not after the fact. A house or addition drawn above its district's Table 11-02 cap, and not covered by a Table 11-04.5 exception, cannot receive a building permit or Zoning Compliance approval from the Planning Division until the design is revised or the applicant obtains a variance for undue hardship. Structures built without that approval are subject to the City's standard zoning enforcement and correction process administered by Boise's Planning and Development Services.
Frequently Asked Questions
How tall can a house be built in Boise's R-1A or R-1B zones?
How does Boise measure building height?
Can I put solar panels or an antenna above my house's height limit?
Does a small infill lot get the same height allowance as a normal lot?
Sources & Official References
Other rules in Boise
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