Accessory Dwelling Units (ADUs) Northern Utah

Ogden City allows internal and detached ADUs in most residential zones. Detached ADUs are limited to 300-800 square feet and cannot exceed 25% of rear yard area. Owner occupancy is required—you must live in either the primary dwelling or the ADU. ADU permits are voided upon property sale, requiring new owners to reapply. South Ogden and other Weber County cities have similar but distinct requirements. We verify the specific regulations for your property before design begins.

ADU construction in Northern Utah typically runs $190-$250 per square foot for building costs, with additional expenses of $25,000-$75,000 for permitting, site preparation, utility extensions, and landscaping. Garage conversions cost less than new detached construction. Total project costs commonly range from $60,000 for smaller conversions to $150,000+ for larger detached units. We provide detailed estimates after evaluating your specific property and requirements.

Most Northern Utah municipalities allow ADU rentals, though restrictions apply. Utah state law prevents HOAs from prohibiting rentals in internal ADUs within owner-occupied single-family homes. However, Layton prohibits short-term rentals in ADUs. Box Elder County restricts occupancy to family members or up to two unrelated individuals. Many jurisdictions require owner occupancy of either the primary dwelling or ADU. We help you understand the rental regulations specific to your location.

Northern Utah ADUs must be engineered for our climate and geology. Roof systems require 35+ psf snow load ratings in valley areas, with higher requirements at elevation. Foundations need freeze-thaw resistant concrete with footings below the 30-inch frost line. The Wasatch Fault Zone requires seismic-compliant construction. Energy codes mandate R-20 wall insulation and R-24+ ceiling insulation. We incorporate all these requirements into every ADU we build.

Yes. Logan's proximity to Utah State University (10,000+ students) allows the city to prohibit internal ADUs in up to 67% of residentially zoned land—compared to 25% in other Utah cities. Cache County mountain and canyon areas have substantially higher snow load requirements (up to 100 psf). We verify the specific requirements for your Cache County property before proceeding with design.

Much of Northern Utah has clay-rich soils that expand and contract with moisture changes. This can cause foundation settling and structural damage if not properly addressed. Areas throughout Weber County, from historic Ogden to North Ogden, commonly have problematic clay soils. We evaluate soil conditions during our property assessment and design foundations to accommodate local conditions, which may include deeper footings or specialized drainage systems.

Internal ADU conversions typically take 2-4 months. Detached ADUs require 4-6 months from permit approval through completion. Permit processing times vary by municipality—some Davis County cities process permits quickly while others require more extensive plan review. Winter weather can affect exterior construction schedules for detached units, though interior work continues year-round. We provide realistic timelines based on your specific project and jurisdiction.

Size limits vary by municipality. Ogden limits detached ADUs to 300-800 square feet. Box Elder County caps ADU size at 40% of the main home's square footage. Utah state law allows municipalities to require minimum 6,000 square foot lot sizes for internal ADUs. We evaluate your lot and local regulations to determine what size ADU your property can accommodate.