New Detached ADU in Florin - Plans, Permits & Build, One Fixed Price

Fast, Reliable New Detached ADU Across Florin

A new detached ADU in Florin typically runs $185,000 to $310,000 all-in, from architectural drawings through final inspection, depending on square footage, foundation work, and whether your 1950s or 1960s home needs a panel upgrade before the unit can be energized. Most Florin projects we take on clear Sacramento County permitting in four to seven months, with construction running another five to eight months after the permit is issued. If you’re planning a detached unit on a 7,000 to 10,000 square foot Florin lot, you’re working with enough room under California’s streamlined ADU law to build without a variance in most cases. Call (971) 497-2402 to schedule a site walk.

Call (971) 497-2402

We’re Ellery ADU Studio, and we’ve designed, permitted, and built 900+ ADUs since 2015. Every Florin project starts with a written price before any work begins, per Haven Standard Clause 1. That’s the whole point of how we operate.

Why Ellery ADU Studio Is Florin’s Preferred New Detached ADU Company

Florin is unincorporated Sacramento County, which means your ADU permit never touches the City of Sacramento’s planning desk. It routes through Sacramento County’s building department instead, with its own fee schedule, its own review timelines, and its own set of ordinances that differ from what a homeowner ten minutes north in city limits deals with. We’ve seen Florin homeowners lose weeks submitting applications through the City’s online portal, only to get a rejection letter explaining they filed in the wrong jurisdiction. We catch that distinction in the first conversation, before you’ve wasted a month.

Nadia Ellery founded this studio in 2015, the same year California’s ADU permitting landscape shifted statewide. We’ve spent the ten years since building a practice around one idea: the permit set is the product. Not an afterthought. Our New Detached ADU team handles the drawings, the structural engineering, the Sacramento County submittal, and the construction under a single contract at a single written price. No designer-versus-builder blame gap. One accountable party.

Florin homeowners also deal with conditions that homeowners in newer subdivisions don’t. This part of the Sacramento Valley sees routine 100°F+ summer highs and dense tule fog through winter. A detached ADU without properly sized mini-split HVAC becomes genuinely uninhabitable by July. And the fog isn’t just a visibility issue. It drives indoor humidity up, and that humidity finds its way into wall cavities fast when an ADU is built over an existing slab-on-grade foundation without a vapor barrier. We design for both, and we document it in the permit set.

Our New Detached ADU Services in Florin

Here’s what we actually build in Florin, and what each option means for your lot, your budget, and your Sacramento County permit path.

Custom Built ADU

Custom built means site-specific framing, foundations, and finishes designed around your exact parcel. On a Florin ranch lot with mature trees, unusual setbacks, or an awkward utility easement, a custom unit often fits better than a prefab module ever could. We draw the plans to match the lot, not the other way around. Most custom detached units in Florin run $210,000 to $310,000 for a 1-bed or 2-bed layout, and that includes the full Sacramento County permit set.

Studio ADU

A studio ADU is the most efficient detached unit we build in Florin, typically 400 to 600 square feet, and it’s the most common choice for homeowners who want a rental unit on a lot where the main house already covers most of the buildable area. In Florin, a studio ADU typically runs $185,000 to $235,000. The tighter the footprint, the more important the vapor barrier and mini-split sizing become, because a small conditioned space with poor ventilation is exactly where Sacramento Valley humidity does its worst work.

Prefab ADU Installation

We specify and coordinate prefab systems from Abodu, Cover, and Dvele within the same single contract that covers your site work, foundation, utilities, and Sacramento County permit. Prefab installation in Florin typically lands between $195,000 and $280,000 depending on the module and site conditions. The advantage is predictability of the factory-built shell. The reality we handle on site is that your 1960s-era utility connections still need upgrades before that shell can be legally occupied, and that work is rarely included in a factory quote.

Modular ADU

Modular units differ from prefab in how they’re assembled and inspected, and in Florin, the Sacramento County inspection path for modular construction requires specific documentation at each stage. We’ve shepherded modular projects through that process enough times to know which submittals get flagged and which sail through. Modular detached ADUs in Florin run $195,000 to $290,000. The floor plans we see most from Florin families are 1-bed units in the 500 to 700 square foot range, often with a kitchenette configured for a parent or an adult child.

1-Bed & 2-Bed ADU

Florin has one of the Sacramento region’s highest concentrations of multigenerational Hmong, Vietnamese, and Latino households. That shapes what gets built here. A 1-bed or 2-bed detached ADU on a Florin parcel isn’t usually a short-term rental play. It’s housing for a grandparent, an adult child, or a newly married couple who want to stay on the family parcel. We size kitchens for daily cooking, not weekend guests. We plan entries that preserve privacy for both households. A 2-bed unit in Florin typically runs $240,000 to $310,000, and the extra bedroom usually adds about $35,000 to $45,000 over a comparable 1-bed.

Trusted Brands We Service in Florin

We specify and coordinate prefab and modular systems from Abodu, Cover, and Dvele for Florin homeowners who want a factory-built shell with site-built site work. What that means in practice: we handle the Sacramento County permit set for your chosen module, we prepare the foundation and utility stubs to the manufacturer’s exact specs, and we take responsibility for the whole installation under our single contract. When a Cover or Abodu module arrives in Florin, our crew is already three weeks into site prep, and the crane date is locked. No finger-pointing between a factory and a general contractor, because there’s only one contract.

We also work with Mighty Buildings and James Hardie products where the project calls for them, but Abodu, Cover, and Dvele are the systems we coordinate most often for Florin parcels.

Common New Detached ADU Problems We See in Florin Homes

• Original 60-100 amp panels feeding cloth-insulated aluminum wiring. We see this on roughly seven in ten Florin ranches built before 1970, and it fails final inspection every time when the ADU load is added. The fix is a panel upgrade to 200 amps plus rewiring of the affected circuits, priced and approved in writing before we open the wall.
• Slab-on-grade foundations with no vapor management. Florin’s winter tule fog drives humidity into the ground, and without a vapor barrier, that moisture migrates up through the slab into the new ADU’s wall cavities. Mold follows within two seasons. We specify a vapor barrier on every Florin detached ADU that ties into an existing slab, and it’s a line item in your written price, not a change order.
• Galvanized supply lines that predate the house’s last major renovation. Many Florin homes still carry original galvanized plumbing, and when an ADU adds demand, the pressure drop becomes obvious. We inspect supply lines before finalizing a permit set and write any replacement into the scope at signing.
• Undersized or water-damaged framing discovered at the tie-in point. Detached ADUs require a weather-tight connection to the existing structure when they share any wall or roofline. We opened a 1962 ranch on Gerber Road and found the original top plates water-damaged from a roof leak that had been painted over for decades. Our crew sistered six undersized rafters and replaced the affected plates, every surprise documented and signed off in writing before we touched it.

Pricing for New Detached ADU in Florin, CA

We Also Serve Cities Near Florin

Our studio coordinates ADU work across California. We build new detached ADUs in Florin and handle projects in Los Angeles, San Diego, San Jose, and San Francisco. If you’re outside Florin proper but still in Sacramento County, your permit path follows the same county process we navigate daily.

FAQs - New Detached ADU in Florin

Get Your Written Price for a New Detached ADU in Florin

Every Ellery ADU Studio project in Florin starts with a written price before any work begins. No exceptions, per Haven Standard Clause 1. We’ll walk your lot, check your panel, assess your slab, and give you a line-item quote that accounts for Sacramento County permits, vapor management, and the realities of your specific 1950s-1970s ranch. If you already have a written estimate from another contractor, bring it. We’ll give you a Free Second Opinion on it. Call (971) 497-2402 to schedule your free estimate.

Written by Nadia Ellery, Owner at Ellery ADU Studio, serving Florin since 2015.