Tempe, AZ Building Safety: Anti-Mansionization (2026)
Key Facts
- Governing section
- ZDC § 3-420(B)
- Trigger
- Any second story on existing 1-story SF home
- Permit type
- Discretionary Use Permit, § 6-308
- Also covers
- Decks, play structures, detached structures
- Exceptions
- Four listed, incl. pre-1987 demolitions
Summary
Tempe requires a discretionary Use Permit before any existing single-story, single-family home can add, expand or rebuild a second story. Zoning and Development Code Section 3-420 puts second-story additions, including detached structures like play structures, through public Use Permit review.
B.Applicability: A Use Permit is required for any single story, single-family residence to add, expand, or rebuild for a second story. This provision is applicable to viewing decks, play structures and detached accessory buildings and structures that have a second story. See procedures and criteria identified in Section 6-308.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: City Code: Supplement 33 Update 4 | Zoning and Development Code: Supplement 11 Update 2).
Full Breakdown
Section 3-420, Single-Family Residential Second Story Addition, Rebuild, targets exactly the kind of out-of-scale addition critics call mansionization: turning a modest single-story house into a bulkier two-story structure that towers over one-story neighbors. Subsection B, Applicability, states plainly that 'a Use Permit is required for any single story, single-family residence to add, expand, or rebuild for a second story,' and the requirement doesn't stop at the main house: it expressly reaches 'viewing decks, play structures and detached accessory buildings and structures that have a second story,' closing off the obvious workaround of building a two-story guest structure or elevated deck instead of a home addition.
A Use Permit under this section runs through the procedures and approval criteria in Section 6-308, meaning the City reviews the proposal publicly rather than issuing it over the counter, weighing compatibility with the scale and character of the surrounding single-story neighborhood before signing off. The section carves out four exceptions in subsection C: homes rebuilt after a prior demolition that occurred before a 1987 ordinance took effect, vacant or newly subdivided lots with no prior single-story residence to compare against, attic conversions that don't touch the existing roofline, and homes that already had two stories, or an approved two-story addition, before this section took effect, along with future two-story accessory buildings or accessory dwelling units tied to those existing homes. Outside those four carve-outs, every second-story project on an existing one-story house needs the discretionary permit.
Violations & Fines
Building, expanding, or rebuilding a second story without the required Use Permit is a Code violation under Section 1-201(A), covering unpermitted construction or alteration of a structure. The City can pursue a civil sanction of $100 to $1,000 per day of noncompliance under Section 1-201(D), or refer the matter as a class 1 misdemeanor in Tempe Municipal Court, punishable by up to a $2,500 fine and up to six months in jail, in addition to requiring the unpermitted addition to be brought into compliance or removed.
Frequently Asked Questions
Can I add a second story to my one-story Tempe house without a permit?
Does the rule apply to a detached structure like a casita or play structure?
Are any homes exempt from this Use Permit requirement?
Why does Tempe require a public Use Permit for this instead of a standard building permit?
Sources & Official References
Other rules in Tempe
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