Architect in Atlanta: 2026 Fees, ADU Rules and City Permits

What architects and ADUs cost in Atlanta

These figures start with national cost data and apply the Atlanta construction cost factor of 0.85 from the U.S. Army Corps of Engineers Area Cost Factors. Design fees and build costs are listed separately. You usually pay the architect months before a builder starts.

Estimates for 2026, including labor and standard parts. Atlanta prices use the metro's construction cost factor of 0.85 (US average = 1.00) from the U.S. Army Corps of Engineers Area Cost Factors. Your quote depends on access, materials and the condition of the home.

The cost estimator below gives design fees and weeks to permit for your project type and ZIP code. A longer version is on the architecture cost estimator page.

How Atlanta architects charge

According to HomeGuide's national figures, residential architects charge 5% to 20% of construction cost, $2 to $15 per square foot, or $100 to $250 an hour.

The fee is usually split by phase:

At the Atlanta factor, hourly rates work out to about $85 to $300. Older intown lots in Decatur and the City of Atlanta usually add a survey and a foundation review, which pushes the fee toward the top of each range. For how fees compare across project types, see the architecture pillar page.

What an addition costs to build

Design is a small share of the whole bill. A 500 square foot addition in Atlanta is priced by the same cost factor, and the total depends on whether you add a bathroom, move the kitchen or go up a story. A second-story addition costs more than a rear bump-out because the existing frame and foundation have to carry the new load. DeKalb County asks for an engineer's letter on second-story work, covered below.

How ADU rules work in Atlanta

Detached ADUs are allowed by right today in the R4, R4A and R5 zoning districts, plus a few special public interest districts and historic districts, according to the Atlanta Department of City Planning. That covers a narrow slice of the city. Most single-family neighborhoods are zoned R1 through R3, and the city's own ADU proposal does not extend ADUs into those districts.

What the city has proposed

City Planning has published a set of changes to make ADUs easier. As written, the proposal would:

• allow attached ADUs such as basement apartments and garage conversions, capped at 50% of the main house or 1,000 square feet
• raise the detached ADU size limit from 750 to 1,000 square feet
• raise the detached ADU height limit from 20 to 24 feet, enough for a second floor or a unit over a garage
• cut the rear and side setback in R4, R4A and R4B to 4 feet, which R5 already allows
• add an ADU allowance to R4B, one unit maximum
• allow three total units in R5, such as a duplex plus an ADU
• count only conditioned space toward the size limit, so garage space would no longer eat into a unit-over-garage allowance
• allow ADUs to be sold separately through a zero-lot-line configuration, one per lot

Ask your architect to confirm the current status before you buy plans for a unit that depends on it. Our ADU design guide covers layouts and cost-saving choices.

The conversion route

In Los Angeles, nearly four out of five ADUs are conversions or expansions of existing space, and only one in five are detached, according to City Planning's own comparison. Atlanta has the same kind of space to convert: basements, garages and attics. A garage conversion in Atlanta runs about $25,500 to $102,000 for 600 square feet, well under a detached build at $76,500 to $127,500. If your lot is zoned R1 through R3, a conversion inside the existing footprint is often the only path that does not need a variance.

Which office reviews your plans

Inside a city, the city issues the permit. In unincorporated areas, the county does. Check the parcel's jurisdiction first. DeKalb and Marietta both warn about this on their permit pages.

City of Atlanta

Every permit type goes through the Accela Citizen portal except Express permits, which are accepted only in person. Residential construction permits need architectural, structural and site plans. The Residential Permits Division handles new single-family and duplex homes up to three stories, additions, decks, patios, basement and attic build-outs, conversions, interior and exterior alterations, retaining walls and sheds. Walk-in service covers residential additions and alterations under 1,500 square feet, Monday to Friday, 8:15 AM to 3:00 PM. The residential line is 404-330-6906.

Since June 25, 2025, under Ordinance 25-O-1341, any applicant whose project may affect trees must hold an arborist meeting with Office of Buildings Arborist Plan Review staff before applying. The meeting comes before the permit application.

The ATL Permit Navigator at permits.atlantaga.gov shows which permits a project needs and what they cost.

Cobb County and Marietta

Cobb County changed how it calculates permit fees on July 1, 2024. Fees are no longer based solely on job costs; they use square footage and flat fees. One- and two-family building permits are charged at $6.00 per $1,000 of estimated construction cost using ICC Building Valuation Data, and the county estimates construction cost as unheated square footage times $31.50 plus heated square footage times $165.67. A $100 site plan review fee applies to new homes, additions, decks, pools, retaining walls and accessory structures. A $15 technology fee applies to all permit types, and trade permits for electrical, plumbing, HVAC and gas cost $80. Building without a permit carries a penalty of double the permit fee, capped at $1,000.

Marietta charges residential permit fees of $4 per $1,000 of total construction cost, labor plus materials, with a $50 base fee and no plan review fee. All permitting is online through SAGES software.

DeKalb County

DeKalb adopted the 2024 ICC codes effective January 1, 2026, per the State of Georgia. For permitting and plan review, residential means single-family detached homes and duplexes only; everything else is commercial. Minimum fees total $245, made up of a $195 minimum permit fee and a $50 certificate of occupancy or completion fee. The county does not accept cash.

Two DeKalb rules affect designers. If a proposed addition sits within 75 feet of a stream, the plans must comply with the DeKalb County Stream Buffer Ordinance. And a second-story addition needs an engineer's letter from a Georgia-licensed engineer detailing the existing structure's and foundation's ability to support the new construction, based on a site inspection. Converting an attached carport or garage to heated floor space requires a site plan or survey review to confirm the zoning district's four off-street parking spaces.

Sandy Springs and Lawrenceville

Sandy Springs requires a residential building permit whenever an owner constructs, alters, enlarges or repairs a building or accessory structure, and also for deck or patio replacements, generators and some play equipment. Cosmetic work such as painting or carpeting does not need one, and neither do detached structures under 120 square feet. After a fire or disaster, emergency stabilization may start first, but the permit must be applied for within 48 hours or the next business day, whichever is sooner.

Lawrenceville issues permits for electrical, mechanical, occupancy, plumbing and structural work through its LPP Portal. A new structure that needs a sewer or water connection first needs a connection permit from Gwinnett Department of Water Resources.

Do you need a permit?

Yes, for any addition, ADU or new home. The question is what the plan set has to contain.

Georgia's state minimum codes are set by the Department of Community Affairs: the 2024 IRC, IBC, IPC, IMC, IFGC, IFC and Swimming Pool and Spa Code, each with Georgia amendments, plus the 2023 National Electrical Code. The 2024 ICC editions and the 2026 Georgia amendments to the 2023 NEC took effect January 1, 2026. The energy code is the 2015 IECC with Georgia Supplements and Amendments, and the metro sits in Climate Zone 3A, warm-humid.

On stamps, the state rule is narrow. Under O.C.G.A. 43-4-14(b)(1), construction documents for one- and two-family residences and domestic outbuildings do not need an architect's seal regardless of cost. Marietta's own FAQ says the same thing in plain terms: Georgia does not require stamped plans for residential structures, but adding or removing loads to an existing structure, or any engineered design, requires a design professional.

Most Atlanta projects end up needing an architect or engineer anyway. A beam where a wall used to be, a second story, a foundation on a slope, a retaining wall over four feet: each of those is engineered work. DeKalb's retaining wall specialty permit starts at four feet. Our guide to permit drawings lists what a complete set includes.

Plan review fees and resubmittals in Atlanta

The City of Atlanta code sets a nonrefundable minimum initial application fee of $175 for all building permit applications, of which $25 funds technology. Permits that need plan review pay 50% of the total building permit fee up front. The building permit fee itself is $7.00 per $1,000 of valuation, with valuation taken from the ICC Building Valuation Data table. Interior alterations without engineered structural work are valued at 20% of new-construction value; with structural engineering, 40%.

Plan revisions that need a third review can cost an extra 25% of the estimated fee or $150 per hour of review, whichever is smaller. An application with no activity for 180 days expires, and extensions cost $100.

Private plan review

Cobb County lets applicants use approved third-party providers for plan review and inspections under 2019 House Bill 493, but the choice has to be made when applying. Atlanta's code refers to the applicant's right under O.C.G.A. 8-2-26 to ask in writing whether an application can be processed within the state time frame. If your schedule is tight, send that letter.

Structural engineering and energy code

Many Atlanta projects need a structural engineer even when the state does not require an architect's seal. Second stories, removed bearing walls, additions over crawlspaces and anything on a slope all qualify. Our guide to structural coordination explains how the engineer's drawings fit into the architect's set.

The energy side is set by the 2015 IECC with Georgia amendments, and the metro is in Climate Zone 3A. In the Georgia IRC amendments, IRC Chapter 11 is deleted and replaced by references to the Georgia State Minimum Standard Energy Code, so the energy compliance path runs through the state document, not the model code chapter. Southface Institute publishes a Georgia residential field guide for the code and runs an energy code hotline at energycodes@southface.org, 404-604-3598.

If you want to see the addition from the street or the kitchen from the new family room before the layout is fixed, ask about 3D renderings.

What local conditions shape the design

Soil, water and foundations

Atlanta's red clay is the Cecil soil series, which covers more than 10 million acres of the southeastern Piedmont and is dominated by kaolinite clay. Kaolinite does not shrink and swell greatly the way some other clays do, so the design concern here is drainage and runoff toward the foundation more than movement. Confirm the series on your lot with a soils report before a foundation is designed.

Rain is spread through the year, with the wettest months July at 4.75 inches, March at 4.68 and January at 4.59, and the driest October at 3.28, per NOAA's 1991 to 2020 normals for Atlanta. Annual precipitation is 50.43 inches. The September 2009 floods put about 20 inches of rain over six days in a narrow band and damaged about 20,000 homes and buildings. Hurricane Helene in September 2024 dropped 12 to 13 inches on the metro, and floodwaters entered at least 200 homes and buildings in greater Atlanta. Site grading and floor elevations matter here.

Heat, cold and storms

Atlanta has a real heating season and a real cooling season. The normals show 47.1 days at 90°F or hotter, 35.7 nights at 32°F or colder, 2,531 heating degree days and 2,051 cooling degree days. That affects window selection, insulation and where you put the mechanical closet.

The March 14, 2008 tornado was an EF2 that tracked six miles through downtown Atlanta at peak winds near 130 mph, damaging at least 50 homes and blowing out windows in the towers. Ice storms matter too: the January 2005 event took power from more than a quarter of a million customers. Talk to your engineer about wind bracing and roof connections.

Termites

Georgia is in what UGA Extension calls the termite belt, and the yard of most Georgia homes holds one or more colonies of subterranean termites. Swarmers fly most commonly from February to April. Any design that puts wood close to soil, or leaves a crawlspace damp, invites termites. Ask how the foundation detail keeps wood clear of grade.

Historic districts

In the City of Atlanta, the Urban Design Commission regulates historic buildings and sites, landmark buildings and sites, conservation districts, historic districts and landmark districts under Chapter 20 of the zoning ordinance. Fences in a historic or landmark district need a Certificate of Appropriateness and an Office of Buildings permit. The permit exemptions that cover ordinary repairs do not apply to exterior work in a landmark or historic district; only repair work under $2,500 needs no certificate or permit there. Check the property on the city's Property Info map at gis.atlantaga.gov/propinfo, and call Office of Design, Historic Preservation at 404-546-0134.

Decatur has the oldest housing stock in the metro, with a median year built of 1975 and 22.7% of units built before 1940, so exterior changes there run into older detailing and, often, older review rules. Historic commissions in Decatur, Marietta, Roswell and Alpharetta were not researched for this page; ask the city before you design.

HOAs

Subdivisions in Gwinnett, Cobb and north Fulton commonly have architectural review committees. Read the covenants before the schematic phase. An HOA can reject a color or a roof pitch that the city approved.

Contracts and payment in Georgia

A contract that requires a residential or general contractor license, signed with a contractor who lacked it, is unenforceable by that contractor, who also has no lien or bond rights, under O.C.G.A. 43-41-17(b). Check the license before you sign.

Mechanics' liens follow a strict deadline. A claim of lien must be filed in the superior court clerk's office of the county where the property sits within 90 days after completion of the work or delivery of materials, and it must include a statement about its expiration and a notice that the owner has the right to contest it. Within two business days of filing, the claimant must send a copy to the owner by registered or certified mail or statutory overnight delivery. The lien action must start within 365 days of filing. Architects, engineers and surveyors have lien rights under the same section.

Lien rights cannot be waived before labor or materials are furnished, and any advance waiver is void. Waivers must follow the statutory forms in at least 12-point type. Ask for the statutory lien waiver with each payment. Our guide to payment protection explains how milestone payments work.

If your architect or builder works inside Atlanta city limits, they also need an Occupational Tax Certificate from the Office of Revenue. The tax is a flat $50 for the first $10,000 of gross receipts plus a class-based rate, and $25 per employee after the first.

Areas we cover

GOLDGCP architects and vetted pros work across Atlanta and the surrounding cities, including:

• Atlanta, including intown neighborhoods and the historic districts
• Marietta
• Alpharetta
• Sandy Springs
• Decatur
• Roswell
• Lawrenceville

Each city runs its own building department. Unincorporated addresses go to the county. Enter your ZIP code to see local prices.