ADU Builder in Folsom, CA

Folsom homeowners have some of the region’s best ADU opportunities — established neighborhoods with mature lots, strong rental demand along the American River corridor, and property values that make a permitted second dwelling a genuine investment. Golden Valley Development is a family-owned, licensed design-build contractor based in nearby Loomis, and we handle Folsom ADU projects end to end: design, engineering, permits, and construction.

ADU options for Folsom properties

Detached ADUs up to 1,200 sq ft — a standalone backyard home: in-law suite, rental unit, home office, or a purpose-built leisure space (golf simulator, theater, gym) engineered for the activity from day one.

Attached ADUs — share a wall and utilities with your main home for a more budget-efficient second dwelling.

Garage conversions — Folsom’s established neighborhoods near the Historic District and older subdivisions convert underused garages into legal, permitted living space — one of the fastest paths to rental income.

Junior ADUs (JADUs) — compact in-home units up to 500 sq ft.

Folsom permitting, handled in-house

Under current California ADU law, most residential parcels can hold a primary home, an ADU, and a junior ADU. Your project runs through the City of Folsom for plan review and inspections, and we manage all of it — site planning, structural engineering, Title 24 energy compliance, and permits — one team from 3D concept to keys.

What a Folsom ADU costs

Most of our custom ADUs land between $150,000 and $400,000 depending on type, size, and site conditions. Our 2026 ADU cost guide breaks down ranges by type, and a free site assessment gets you a real number for your specific lot.

A local team, minutes away

We’re based in Loomis — a short drive up the hill — CSLB licensed (#1030793) and insured. You’ll see your ADU in 3D before we build, and we’re currently taking $1,000 off design.

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

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