Salt Lake City, West Valley, West Jordan, Sandy, South Jordan, Draper, Murray, Riverton, Herriman and Cottonwood Heights: the county's biggest gotcha is that Salt Lake City permits buildings at a lower size threshold than most Utah cities, and has specific accessory-building size and setback caps.
While much of Utah exempts accessory buildings up to 200 sq ft, Salt Lake City requires a building permit for anything over 120 square feet. And any size in a Historic District. Most other Salt Lake County cities (and the unincorporated/Greater Salt Lake MSD areas) follow the 200 sq ft default. Always confirm the threshold for your specific city before assuming.
| Code criteria (Salt Lake County) | Value | What it means for your build |
|---|---|---|
| Building-permit threshold | 120 sq ft (SLC) · 200 elsewhere | SLC is stricter; Historic Districts require a permit at any size. |
| Ground snow load | 28 psf valley floor (≤4,239 ft) | Above 4,239 ft (Draper, Sandy, Cottonwood, Herriman benches) climbs sharply. |
| Design wind speed | 115 mph (SLC res) · 105 (MSD) | Canyon-mouth sites warrant a site evaluation. |
| Seismic design category | D2 residential | Wasatch Fault. Engineered anchorage required. |
| Frost / footing depth | 30″ (more at elevation) | Foundation bears below frost line. |
| Adopted codes | 2021 I-codes · 2020 NEC | Statewide since July 1, 2023. |
Figures shown are valley-floor / Salt Lake City values; benches and canyons are higher. Verify with your city building department.
Salt Lake City publishes unusually specific rules for detached garages and accessory buildings. They're a useful benchmark. But they're SLC-specific, and neighboring cities set their own:
Larger shops and garages are very doable. They may need a conditional use, a variance, or placement on a larger or differently-zoned lot. We'll help you size the building to your zone before you commit.
In Salt Lake City, anything over 120 sq ft needs a building permit (any size in Historic Districts). In most other Salt Lake County cities and unincorporated areas, the threshold is 200 sq ft. A metal garage or shop with a foundation and electrical requires a permit regardless of city.
The Salt Lake valley floor (at or below 4,239 ft elevation) uses a 28 psf minimum ground snow load. Above that line, including the east-side benches of Draper, Sandy, Cottonwood Heights and Herriman, plus the canyon areas, the load rises quickly with elevation. We engineer to your address-specific value, not the valley minimum.
Over 120 sq ft requires a building permit in Salt Lake City. And any size in a Historic District. Many neighboring cities use 200 sq ft, so confirm with your specific jurisdiction.
Accessory coverage is capped at 50% of the principal structure, up to 720 sq ft for single-family lots, with a peak height of about 17 ft. Bigger buildings are possible with the right zoning or approvals.
28 psf on the valley floor (≤4,239 ft elevation). Bench and canyon properties above that elevation are higher. We engineer to your exact site value.
Yes. Every building includes PE-stamped engineering prepared for your loads and jurisdiction.
Get instant pricing, then a firm quote with engineering sized to Salt Lake County code.