ADU Design & Construction in Grass Valley
Custom Accessory Dwelling Units built for homeowners. Designed to last, built with care, permitted with confidence.
⛨ Licensed & Insured - CSLB #935362 ⚲ Local Contractor
Built locally. Built to last.
Whether you call it a granny flat, a backyard cottage or an ADU, the first thing to figure out is what your property will allow. Septic and a well when your property has them, slope, lot size and local rules all shape where an ADU can go and what it costs.
An ADU is often for someone close: a parent moving nearby, family who needs their own space, or a renter whose rent helps carry the property. That raises the stakes. You want it done right, you want to stay in the loop, and you want someone who will actually finish.
If you're not sure an ADU fits your property yet, start with our guide to building an ADU for local requirements and what to expect. If you're building in Auburn, Granite Bay or elsewhere in Placer County, our Placer County ADU page covers real costs and permitting there.
We design and build ADUs as one team, from the first site walk through the final walkthrough, and we handle the permits along the way. You get honest updates, and you hear about changes from us first.
Three ways to add an ADU to your home
Detached ADU
A fully independent structure built in your backyard with its own entrance, kitchen, and bathroom, ideal for rentals or guest housing.
Building Conversion
Transform an underused garage, barn, or other outbuilding into a comfortable, code-compliant living space without expanding your home's footprint.
Attached & Junior ADU
A new addition built onto your existing home, or a junior ADU of up to 500 square feet created within it. Either way, a private, self-contained living space.
WHAT WE BUILD
ADU SERVICES OFFERED
We handle every stage of the ADU process so you are not juggling multiple contractors or consultants.
Detached ADUs
Standalone backyard units, designed and built from the ground up to suit your lot and lifestyle.
Building Conversions
Convert a garage or outbuilding into a fully livable space: efficient, affordable, and code-ready.
Design and Build
A complete design-build process so you have one trusted team from concept to keys. If your project also involves improving your existing house, we can coordinate home remodeling and additions alongside your new ADU.
Why homeowners build ADUs
✔ Rental Income - Generate steady monthly income from a long- or short-term rental.
✔ Property Value - Add significant resale value to your home and property.
✔ Family Housing - Keep loved ones close while giving everyone their own space.
✔
Flexible Use - Office, studio, gym, guest house. Adapt the space as needs change.
TRUSTED LOCALLY
Why Homeowners Choose Green Bee
Our experience also includes custom home construction, allowing us to bring the same level of craftsmanship, planning, and attention to detail to every ADU we build. We have spent years building in Nevada County, and that local experience makes a real difference at every stage of your project.
✔ Detached ADUs, garage and outbuilding conversions, and attached and junior ADUs
✔ Design and build with one team, from your first sketch through the final walkthrough
✔ We handle the permits, from plans and submittals to inspections
✔ Honest updates, calls returned, and problems named early
✔ Almost two decades of construction experience, building in Nevada County since 2009
✔ Licensed, bonded and insured, and an NCCA member
✔ One-year workmanship warranty, extended to five years through our annual maintenance program
Learn more about our team.
INVESTMENT
How Much Does an ADU Cost?
An ADU typically runs $100K to $300K+. Every ADU is unique. Final cost depends on the type, size, finishes, and site conditions.
What moves the number:
- Size and square footage
- Detached vs. attached vs. garage conversion
- Site preparation and utility hookups
- Finish level: standard, mid-grade, or premium
- Permits and local impact fees
An accurate number starts with a site walk. We'll walk your property with you and tell you what we see.
REVIEWS
What Homeowners Say
"I moved into a Green Bee Construction ADU in Grass Valley and honestly the quality speaks for itself. The loft space, the custom wood ladder, the kitchen finishes, the stained concrete floors. It's clear this wasn't built to just pass inspection."
Rachelle, Grass Valley · Google review
"Being in the HVAC trade myself, I have seen numerous ADU renovations throughout Nevada county, and given what I’ve seen, I would highly recommend Green bee construction For any of your renovation needs"
Chris T. · Google review
OUR PROCESS
How an ADU Project Works With Green Bee
FEATURED PROJECT
Garage Conversion ADU Project
A complete garage conversion turned an underused space into a bright, modern one-bedroom unit. The project included new insulation, a full kitchen, custom millwork, and energy-efficient windows, all permitted and inspected to current Nevada County standards.
Looking for more inspiration? Explore our
ADU Gallery to see additional completed ADU projects, design ideas, and the quality craftsmanship we bring to every build across Nevada County.
FAQ
Common Questions About Building an ADU
How long does it take to build an ADU?
Most ADU projects take 6 to 12 months from initial design through final inspection. Garage conversions are typically faster than ground-up detached builds.
Do I need a permit for an ADU in Nevada County?
Yes. All ADUs require permits from Nevada County. We handle the entire permitting process for you, including plans, submittals, and inspections.
Can I rent out my ADU?
Yes. ADUs in California can be rented as long-term rentals. Local short-term rental rules vary, so we'll help you understand what applies to your property.
How big can my ADU be?
Detached ADUs in California can typically be up to 1,200 sq ft, depending on lot size and local rules. We'll review your site and recommend the best size for your goals.
Do you handle the design too?
Yes. We offer full design-build services so you have one trusted team from your first sketch through the final walkthrough.
What warranty do you offer?
A one-year workmanship warranty, extended to five years through our annual maintenance program. See how the program works on our warranty page.
Service Areas
We build ADUs throughout:
Grass Valley Nevada City Penn Valley Auburn Lake Wildwood Lake of the Pines Alta Sierra Meadow Vista Truckee Granite Bay
and surrounding Nevada and Placer County communities.
GET STARTED TODAY
Start your ADU project
If you are thinking about building an ADU, the first step is a conversation about what is possible on your property. Contact Green Bee Construction to schedule a consultation and get a clear plan for moving forward.
