Home / ADUs & In Law Suites
ADU Builderin Raleigh, Cary & Apex
In law suites · Backyard cottages · Garage conversions
Room for aging parents, grown kids or guests, on the lot you already own. We check your town's rules first, then design and build it with one written price.
See If My Lot Fits an ADU✓ Lot and zoning check first ✓ Written, line item price ✓ Licensed NC general contractor
ADU builder in Raleigh, NC
More Room for Family Without Moving
Families across the Triangle are running out of room. A parent needs to move closer. A grown kid needs a place to land. You want guests to have their own door. Buying a bigger house in Raleigh, Cary or Apex is expensive, and you like where you live.
That's where an ADU or in law suite comes in. It's a second, smaller living space on your lot with its own bedroom, bathroom and often a kitchen. As an ADU builder in Raleigh, Sanderson Construction plans and builds attached in law suites, detached backyard cottages and garage conversions.
We're a local, licensed NC general contractor based in Holly Springs, with over 20 years of building and remodeling in the Triangle. Sam leads every project. Before anyone draws a plan, we check what your town allows on your lot.
We build ADUs and in law suites in Raleigh, Cary, Apex, Holly Springs, Fuquay-Varina and Morrisville.
Your options
Three Ways to Add an ADU or In Law Suite
The right choice depends on your lot, your budget and how much privacy you want.
Attached in law suite
An addition built onto your house with its own bedroom, bathroom and sitting area. Easy for a parent to stay close. Often shares utilities with the main home.
- Close to family
- Can include a small kitchen
- Built as a home addition
Detached backyard cottage
A separate small home in your backyard. The most privacy for everyone, and the most flexible for guests or family.
- Own front door
- Full kitchen and bath
- Needs space for setbacks
Garage conversion
Turn an attached or detached garage into finished living space. Uses a structure you already have.
- Reuses existing walls and roof
- Often quicker to plan
- Lose garage parking
Not sure which fits? That's what the walkthrough is for.
Raleigh ADU rules
What Raleigh Allows
Where. The City of Raleigh allows ADUs in the R-1, R-2, R-4, R-6, R-10, RX, OX, NX, DX and CX zoning districts.
Size. Raleigh says ADUs are typically 450 to 800 square feet, and ADUs of 1,000 square feet are allowed on specific sites. The ADU has to be smaller than the main home.
How many. One ADU per lot. Lots in a Frequent Transit Area may add two.
Selling. An ADU can't be sold apart from the main home.
Parking. Raleigh does not require extra parking for an ADU.
Historic districts and HOAs. In a Historic Overlay District you need a Certificate of Appropriateness before building. HOA rules may also apply.
Source. These points come from the City of Raleigh ADU FAQ. Rules change, so we confirm them for your lot before design.
Cary, Apex and nearby towns
ADU Rules Outside Raleigh
Cary. The Town of Cary expanded its ADU rules in 2025. The Town Council adopted the change on April 10, 2025, and it took effect June 2, 2025. ADUs are now allowed in all residential zoning districts where detached homes are allowed. They can be detached backyard cottages, converted garages or attached additions. Setbacks still apply, size limits depend on your lot and main home, and HOA rules may apply too.
Apex, Holly Springs, Fuquay-Varina and Morrisville. Each town has its own development ordinance and its own rules for accessory units. Lot size, setbacks and utility connections all matter. We read your town's current ordinance for your address before we design anything, so you don't pay for plans you can't build.
HOAs. Many Triangle neighborhoods have HOA covenants that limit what you can build. Check yours early. Sam can help you know what to ask.
What clients say
Families Who Added Space With Sam
"Sanderson did an excellent job on our home addition. They facilitated the design and implementation to exactly what we wanted, and allowed us to stay in our home while construction was underway with only minor inconveniences. Sam's crew was made up skilled craftsman who were also kind and respectful. We are very pleased with our new addition, have no negative comments and would recommend Sam and his crew for any building project."
Laurie P. · Google review
"Sam and his team are top notch in my opinion. If you are looking for excellent quality and expertise to turn your vision into reality, look no further. These guys do it right. I highly recommend Sanderson Construction for all of your additions, kitchen, bathrooms, patios, decks, and more."
Mike K. · Google review
Your lot check
Find Out What Your Lot Allows
Sam will look at your lot, your town's rules and your goals, then tell you what you can build and what it will cost. No pressure.
See If My Lot Fits an ADU(919) 868-8958What drives the price
What an ADU or In Law Suite Costs
Every ADU is custom, so we don't post a starting price. These are the things that move the number most.
- Attached or detached. An attached in law suite can share walls, roof lines and utilities with your home. A detached cottage needs its own foundation, roof and utility runs.
- Size. More square feet means more framing, finishes and time. Your town also caps the size.
- Kitchen and bath. A full kitchen and bathroom add plumbing, electrical and fixtures.
- Utilities and site work. Running water, sewer and power to a backyard unit, plus grading and access, can be a big line.
- Permits and plans. ADUs need building permits and inspections. We handle them and include them in your written price.
You'll see each of these as its own line on your written price. For more on planning, read what to know before building a home addition in Wake County.
How it works
From Lot Check to Move In
Lot and rules check
Sam walks your lot and we check your town's zoning, setbacks and HOA limits. You'll know what's possible before you spend money on plans.
Design, price and permits
We plan the layout with you, give you a written, line item price and timeline, and pull the permits.
Build and final walkthrough
Our crew builds it and keeps you posted. Sam walks the finished space with you before we call it done.
Straight answers
ADU and In Law Suite Questions
What is an ADU?
An ADU, or accessory dwelling unit, is a second, smaller home on the same lot as your main house. It can be attached, like an in law suite addition, or detached, like a backyard cottage. It has its own living space and usually its own kitchen and bathroom.
What's the difference between an ADU and an in law suite?
People use the words in different ways. An in law suite usually means private living space for a family member, often attached to the main house. An ADU is the zoning term for a second dwelling on the lot. On the walkthrough, Sam will help you sort out which one your town says you're building.
Can I build an ADU in Raleigh?
Raleigh allows ADUs in many residential and mixed use zoning districts. Its ADU FAQ says ADUs are typically 450 to 800 square feet, some sites allow up to 1,000 square feet, the ADU must be smaller than the main home and it can't be sold separately. We check your exact lot before design.
Can I build an ADU in Cary?
Yes, in many cases. Cary expanded its ADU rules in 2025, and ADUs are now allowed in all residential zoning districts where detached homes are allowed. Setbacks, size limits and HOA rules still apply.
Do I need extra parking for a Raleigh ADU?
According to the City of Raleigh ADU FAQ, additional parking is not required for an ADU.
How much does an ADU or in law suite cost?
Every ADU is custom, so we don't post a starting price. Size, attached or detached, plumbing, utilities and site work all change the number. After Sam walks your lot, you get a written, line item price.
What about my HOA?
Town rules are only part of it. Many Triangle neighborhoods have HOA rules too. Both Raleigh and Cary point out that HOA rules may apply, so we ask you to check yours early.
How do I find out if my lot fits an ADU?
Book a walkthrough with Sam using the form on this page or call (919) 868-8958. We look at your lot, your town's rules and your goals, then tell you what's possible.
Keep reading
More From Sanderson Construction
Your lot check with Sam
Ready to See If Your Lot Fits an ADU?
Tell us who the space is for and what you have in mind. Sam will check your lot and your town's rules, then send you a written, line item price.
See If My Lot Fits an ADU(919) 868-8958Book a Walkthrough With Sam
Tell us about your kitchen, bathroom, ADU or addition. Sam will set up a time to walk your home, then send you a written, line item price. Serving the Triangle for over 20 years.
Cary, Apex, Holly Springs, Fuquay-Varina, Morrisville & Raleigh, NC