Accessory Dwelling Units (ADUs) in Durham, NC
Radford Building Company designs and builds ADUs across Durham, backyard cottages, in-law suites, and garage conversions, with the zoning, permitting, and full cost handled before construction starts.
More Durham homeowners are building ADUs for three reasons: rental income in a city with steady demand near Duke and downtown, a private space for aging parents or adult kids, and a real home office or guest suite that isn’t just a spare bedroom. What legally separates an ADU from a bonus room is the kitchen. Once a space has its own entrance, kitchen, bathroom, and sleeping area, Durham’s code treats it as a second dwelling, and that classification changes everything about how it gets permitted and built. Radford Building Company is a Durham-based design-build firm, so we handle the design and the construction of that second dwelling under one contract.
The part that catches most people off guard in Durham isn’t the construction, it’s the rules and the fees. Durham allows one ADU per lot, it has to stay clearly smaller than your main house, and the property has to keep a single-family look from the street. An ADU here is an administrative approval rather than a special use permit, which is good news, but any detached unit or project over $30,000 needs engineered plans, and the sewer connection impact fee for a new dwelling unit has historically run over $20,000 before a single nail goes in. We walk you through all of it, and our detailed guide on ADU cost and rules in Durham breaks the numbers down before you commit to anything.
There are three ways to add one, and the right answer depends on your lot and budget. A detached backyard cottage feels the most independent and is the most flexible for rental. An attached unit built as an addition with a private entrance is usually cheaper because it doesn’t need a new foundation. And a conversion of an existing garage or basement reuses space you already have. We evaluate all three against your lot’s zoning and your budget before design starts, so you’re building the version that actually pencils out.
What a Radford ADU Covers
We build all three ADU types Durham allows. A detached backyard cottage is a stand-alone structure with its own foundation, the most private option and the one most people picture for a rental. An attached ADU is built onto your existing home with a separate entrance, and because it shares a wall and foundation, it usually costs less than building from the ground up. A garage or basement conversion turns space you already own into a legal dwelling, which can be the most cost-effective route when the existing structure cooperates.
Whichever type fits, a Radford ADU is a complete, self-contained home in miniature: a full kitchen, a bathroom, a sleeping area, its own entrance, and its own systems. Because it’s a second dwelling on your lot, the utility connections, the setbacks, and the size limits all have to be right, not approximate. We handle the engineered plans, the mechanical and utility work, and the finish carpentry in-house, so the unit is compliant and comfortable rather than a permitting headache. Many of our ADU clients are planning for multigenerational living or long-term rental income, and we design the space to hold up to that kind of daily use.
Why Choose Radford in Durham
We’re based in Durham at 127 Wolfpack Drive, so the City-County Inspections Department, the zoning map, and the impact-fee reality aren’t abstractions to us. On an ADU, that local knowledge is most of the value. The single biggest reason Durham ADU projects fall apart is that the owner doesn’t find out about the sewer impact fee or their lot’s zoning eligibility until they’re already spending money. We check whether your lot allows an ADU by right and we put every fee on the table during pre-construction, before you’re committed.
The design-build model matters more here than on almost any other project. An ADU is small, but it carries the full complexity of a house: design, engineering, permitting, and every trade, packed into a tight footprint and a tight budget. When one team owns all of it, the drawings and the bids don’t drift out of sync, and the price you approve is the price you plan around. We’re a member of the Home Builders Association of Durham County, BBB-accredited, rated 5 out of 5 on Houzz, and we back our work through RWC warranty coverage.
How the Process Works
- Feasibility & consultation. We visit your Durham property, check your lot’s zoning and ADU eligibility, and talk through your goal, whether that’s rental income, family, or a home office, and your budget. This is where the impact fees and site constraints get identified, not after you’ve committed.
- Design & pre-construction. We design the ADU and produce the engineered plans Durham requires for detached units, and we define every selection, fee, and cost in writing. You approve a clear scope and price before any work begins.
- Selections. You choose finishes, fixtures, and materials at your own pace, with our team guiding the decisions and keeping every choice inside the budget you approved.
- Construction & Certificate of Occupancy. Your dedicated project manager runs the build and schedules the city inspections at footings, foundation, framing, rough-ins, insulation, and final. Once the final inspection passes, you receive the Certificate of Occupancy that makes the unit legal to occupy or rent.
More in Durham
This is one of the services we offer across Durham. Head back to our Durham home builder and renovation hub to see everything we do in the city, or explore our other Durham services: kitchen remodeling and additions & renovations. Radford also builds and renovates across Chapel Hill, Hillsborough, and the wider Triangle. See every area we cover on our service area page.
What makes a space a legal ADU in Durham?
The kitchen. Once a space has its own entrance, kitchen, bathroom, and sleeping area, Durham’s code classifies it as a second dwelling unit rather than a bonus room. A range or built-in cooktop is what triggers that legal classification.
Do I need a permit to build an ADU in Durham?
Yes, but not a special use permit. An ADU in Durham is an administrative approval submitted to the City-County Inspections Department, with plan review typically taking one to two weeks. Any detached ADU or project over $30,000 requires engineered plans. We handle the submission and the inspection schedule for you.
How much does an ADU cost in Durham?
ADU cost varies more than almost any other project because starting conditions differ so much, and the fees surprise people. Durham’s sewer connection impact fee for a new dwelling unit has historically run over $20,000 before design or permits. A garage conversion and a ground-up backyard cottage are very different numbers. We define your full cost, fees included, in pre-construction. Our ADU cost and rules guide for Durham walks through the details.
Can I build more than one ADU, or build one on any lot?
Durham allows only one ADU per lot, and the lot must meet the minimum area for its zoning district. The ADU also has to stay clearly smaller than your primary home, and the property has to keep a single-family appearance from the street. We confirm your lot’s eligibility before design.
Can I rent out my Durham ADU?
Yes, once it passes final inspection and receives a Certificate of Occupancy. That’s the point at which the unit is legal to occupy or rent. Many of our ADU clients build specifically for rental income or multigenerational living.
See Our ADUs Gallery
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