ADU Builder in Granite Bay, CA

Granite Bay’s large estate lots are made for ADUs. With generous acreage, privacy, and some of the region’s finest homes, a detached second dwelling here isn’t a compromise — it’s an amenity. Golden Valley Development is a family-owned, licensed design-build contractor based minutes away in Loomis, and we design and build custom ADUs across Granite Bay finished to the same standard as the main house.

What we build in Granite Bay

Detached ADUs up to 1,200 sq ft — a private guest house, in-law residence, or purpose-built leisure space: golf simulators, home theaters, gyms, and studios with the ceiling heights, power, and sound engineering specified for the activity.

Attached ADUs — a seamless, architecturally matched addition to your home.

Garage conversions and JADUs — turn existing square footage into legal, permitted living space.

Granite Bay permitting — through Placer County

Granite Bay is unincorporated, so ADU projects here run through Placer County rather than a city hall — a different plan-review process with its own requirements. We work in the county’s system constantly from our Loomis headquarters and handle site planning, engineering, Title 24 compliance, and permitting in-house, so your project moves as one process from 3D concept to final inspection.

What a Granite Bay ADU costs

Most of our custom ADUs land between $150,000 and $400,000; larger estate builds with premium finishes run higher. Our 2026 ADU cost guide covers ranges by type, and a free site assessment gets you a real number for your specific parcel.

Built by neighbors

We’re Loomis-based — next door to Granite Bay — CSLB licensed (#1030793) and insured. See your ADU in 3D before we break ground, with $1,000 off design right now.

Get your free Granite Bay site assessment → or call (916) 671-0802.

Also serving Roseville, Rocklin, Folsom, El Dorado Hills, Loomis, and greater Placer County.