From Single‑Family to Duplex in Decatur: A Playbook

Turning a single-family home into a duplex in Decatur can feel like a maze. You want extra income, flexibility for multigenerational living, or a smart house-hack, but you also need a clear, low-risk path. The good news: with the right steps, you can vet feasibility in days, avoid costly surprises, and move from concept to new keys in hand.

This playbook walks you through exactly how to do it. You’ll learn how to confirm the right jurisdiction, map feasibility from your laptop, solve for parking, plan a code-compliant design, and follow a de-risked sequence from first sketch to final inspection. Let’s dive in.

First step: confirm the right jurisdiction

Before you fall in love with a property, confirm whether it sits inside the City of Decatur or in unincorporated DeKalb County. Many “Decatur” addresses are actually in the county. The rules change based on jurisdiction, so this is your first legal checkpoint.

• If the property is inside city limits, follow City of Decatur planning, zoning, historic preservation, building permits, and stormwater rules. Start with the City’s Community Development hub for planning and permitting contacts and procedures. You can explore the department portal at the City of Decatur’s Community Development page.
• If the property is outside city limits, you’ll work with DeKalb County. The Department of Planning & Sustainability covers zoning and entitlement questions. Begin at the DeKalb County Planning & Sustainability page.

When in doubt, verify with parcel/GIS tools. DeKalb County offers an online GIS portal that helps you confirm jurisdiction and parcel details. For borderline cases, call or email the relevant planning office and save a written summary of what they confirm.

Quick feasibility mapping checklist

You can eliminate most non-viable options with one short desk review. Here’s the sequence to follow before any site visit.

Parcel and zoning lookup

• Confirm jurisdiction: City of Decatur or unincorporated DeKalb County.
• Identify the zoning district and whether two-unit dwellings are permitted by right, by conditional use, or not allowed.
• Note minimum lot area and frontage, setbacks, height limits, and maximum lot coverage or floor-area rules.

Physical parcel checks via aerials and GIS

• Lot size, shape, and slope. Narrow or steep lots complicate separate entries and parking.
• Existing building footprint and yard area. Look for space to add a second entrance, a small landing, or parking pad.
• Driveway and curb cuts. Count existing curb cuts and measure width as best you can.
• Trees and canopy. Flag any large, likely protected trees that may limit where you can add parking.
• Sewer vs septic. In close-in Decatur areas, conversions typically assume sewer. If a parcel is on septic, feasibility may drop quickly.

Neighborhood context and overlays

• Historic district boundaries. In City of Decatur’s local historic districts, exterior changes often need review by a preservation board.
• Parking environment. Look for on-street restrictions, permit zones, or limited supply that may push you to add off-street spaces on site.
• Transit proximity. Being near MARTA can reduce parking demand and improve rentability. Explore routes and stations at MARTA’s official site.
• Floodplain or conservation areas. These can affect design, insurance, and timelines.

Preliminary size and space feasibility

• Sketch a high-level split: upstairs/downstairs, front/back, or a 1-bedroom plus 2-bedroom mix.
• Confirm the potential for separate entries and compliant egress for bedrooms.
• Think through where you could place a second kitchen and how utilities might be separated.

Approvals and timing scan

• Look up plan review and permit fee schedules in your jurisdiction’s portal.
• If you might be in a historic district, note meeting schedules and submission deadlines so you can budget time.

Create a one-page feasibility sheet with: jurisdiction and zoning, permitted use status for a duplex, minimum lot area and setbacks, sewer availability, presence of historic or other overlays, curb cut and parking count, trees and slope flags, and a quick rent comp check.

Parking and site constraints

Parking is often the gating factor. Planners will flag it early, so you should, too.

What to expect locally

• Minimum off-street spaces per unit. Many residential districts require 1 to 2 spaces per unit. Verify whether tandem parking counts and whether on-street spaces can be credited.
• Driveway and curb cuts. Public works controls curb cut width, spacing from intersections, and the number of cuts. Widening or adding a curb cut typically needs a permit.
• Impervious surface and stormwater. New paving can push you over impervious limits or trigger stormwater requirements.
• On-street restrictions. Permit zones or time-limited streets make on-site solutions more important.

Practical strategies that work

• Maximize the existing driveway. Tandem spaces often solve the count without new pavement when allowed.
• Consider a modest widening. If code permits, a few extra feet can unlock a second space. Confirm curb cut rules before you draw it.
• Use permeable materials. Permeable pavers or reinforced gravel can help manage impervious limits while creating durable parking pads.
• Explore rear access. Some parcels have alleys or easements that support rear parking and cleaner streetside elevations.
• Lead with a site sketch. A simple plan that shows space dimensions, turning radii, and materials will make planner conversations productive.

Common pitfalls to avoid

• Assuming you can widen the driveway without a curb cut permit.
• Forgetting maneuvering space. Vehicles must enter and exit without encroaching on sidewalks or the public right-of-way.
• Underestimating grading costs on sloped lots, including retaining walls and erosion control.

Design, code, and utilities: what your plan must do

A well-planned conversion hits life-safety, comfort, and billing clarity at the same time. Your architect and contractor will align design with the locally adopted versions of Georgia’s State Minimum Standard Codes.

Building code fundamentals

• Unit separation and fire safety. Expect rated separations between units, plus smoke and carbon monoxide detectors.
• Means of egress. Each sleeping area needs a compliant egress window or door. Stairs, landings, guards, and handrails must meet width and rise/run rules.
• Kitchens and baths. Ventilation, GFCI/AFCI protection, and proper clearances are standard plan review items.
• Inspections and certificate of occupancy. You will need an approved permit, progress inspections, and a final CO before occupancy.

Utilities and metering

• Electrical and gas. Many owners choose separate meters so each household pays its own usage. Panel capacity upgrades are common.
• Water. Municipal systems often keep one main meter per parcel. Ask about sub-metering rules and how landlords can bill tenants for usage.
• Sewer capacity. Confirm a sanitary sewer connection and lateral sizing can handle an extra unit. Conversions on septic can require major upgrades or may not be feasible.
• HVAC and hot water. Independent systems per unit simplify comfort and billing. Plan ahead for condenser placement and vent terminations.

Quiet, privacy, and livability

• Sound attenuation. Add insulation, resilient channels, and acoustical seals where you split units.
• Light and privacy. Preserve egress and natural light while orienting entries so each unit feels private.
• Storage and access. Provide secure mail and package locations, bike storage, and clear wayfinding for each entrance.

Historic preservation considerations

If the home sits in a local historic district, exterior changes like new doors, windows, stoops, or exterior stairs typically require design review. Interior layout changes are often more flexible, but exterior mechanical placement, window alterations, and materials will be scrutinized. Build in time for a Historic Preservation Commission review if applicable.

Health, safety, and landlord duties

For homes built before 1978, federal lead rules apply if you disturb painted surfaces. Learn about safe work practices and requirements at the EPA’s Renovation, Repair and Painting Program page. Ensure you install code-compliant smoke and carbon monoxide detectors and check whether your jurisdiction requires rental registration or a business license before leasing.

A de-risked project sequence from concept to lease-up

Move in a clear order so you do not pay for drawings you cannot use or lose months to avoidable surprises.

Step 0: Market and finance pre-check (0 to 7 days)

• Pull rent comps for 1-bedroom and 2-bedroom units near your target micro-location.
• Confirm your loan path. FHA and conventional lenders have options for 2 to 4 units when you live in one unit. Start with HUD’s Single Family overview to understand owner-occupied 1 to 4 unit financing basics.
• Deliverable: go or no-go based on rent coverage and financing.

Step 1: Jurisdiction and zoning confirmation (0 to 7 days)

• Use GIS to confirm City vs County, zoning district, and whether two units are allowed.
• Call or email the planning office with two direct questions: “Can this parcel have two dwelling units?” and “Are there historic or overlay constraints?”
• Deliverable: written note summarizing the permit pathway and any variances or conditional use.

Step 2: Concept sketch and cost range (7 to 14 days)

• Hire an architect or experienced designer for a quick feasibility study and floor plan sketch that shows entries, egress, and parking.
• Ask a GC for a ballpark cost for separation walls, kitchens, baths, HVAC, electrical upgrades, meters, and fees.
• Deliverable: feasibility sketch, budget range, updated go or no-go.

Step 3: Pre-application meeting (2 to 4 weeks to schedule)

• Many jurisdictions offer pre-app meetings. Bring your sketch, a basic site plan, and questions on parking, curb cuts, and historic review.
• Deliverable: list of required plans, fees, approvals, and an estimated timeline.

Step 4: Detailed design and permits (4 to 12+ weeks)

• Prepare construction drawings for structure, egress, mechanical, plumbing, and electrical. If applicable, add historic district exterior elevations and materials.
• Submit permits, pay fees, and address plan review comments. Prepare variance or conditional use materials if needed.
• Deliverable: approved building permit and any zoning approvals.

Step 5: Procurement and mobilization (2 to 6 weeks)

• Select a GC with small multifamily or conversion experience.
• Order long-lead items like windows, HVAC equipment, and cabinets.
• For pre-1978 homes, ensure contractors follow RRP requirements.

Step 6: Construction and inspections (8 to 24+ weeks)

• Proceed through demolition, framing, rough trades, insulation, and finishes, with inspections at each stage.
• Coordinate utilities for separate meters or approved sub-metering. Confirm unit addressing with USPS and 911 if needed.
• Deliverable: final inspections passed and Certificates of Occupancy issued.

Step 7: Pre-leasing and lease-up (4 to 8+ weeks)

• Capture photos, floor plans, and clear unit descriptions. Set rents based on comps and your net operating income target.
• Confirm any rental registration or business license requirements. Prepare lease forms, deposit handling, and move-in checklists.
• Deliverable: signed leases and utility billing arrangements in place.

Step 8: Post-occupancy maintenance and compliance

• Schedule routine HVAC service, filter changes, pest control, and safety device checks.
• Track property tax reassessment. Budget for a likely increase after conversion.

Local resources to speed things up

• City of Decatur Community Development: planning, permitting, and code contacts. Visit the City of Decatur’s Community Development page.
• DeKalb County Department of Planning & Sustainability: zoning questions and entitlement pathway. Explore the DeKalb County Planning & Sustainability page.
• DeKalb County GIS: parcel and jurisdiction confirmation. Use the DeKalb County GIS page.
• HUD Owner-Occupied 1 to 4 Unit Financing: learn program basics for FHA-backed options. See HUD’s Single Family overview.
• EPA RRP Lead Rules: required practices for pre-1978 homes. Visit the EPA’s Renovation, Repair and Painting Program page.
• Transit Context: review MARTA routes and stations that can influence parking needs and renter demand at the MARTA website.

Final thoughts and next steps

Converting a single-family home to a duplex in Decatur is very doable when you sequence it well. Start with the jurisdiction check, test parking on paper, and get a quick sketch and cost range before you spend big on plans. Treat historic review and any needed variances as schedule risks, and build in a budget contingency for older-home surprises.

If you want a second set of eyes on feasibility or you are searching for the right candidate property, let’s talk. We specialize in renovation-forward purchases and can connect you with trusted architects, contractors, and lenders who know Decatur. Ready to map your plan or value your current home as part of a move-up strategy? Get in touch with Unknown Company to get started and Get Your Home Value.

FAQs

Can I convert any Decatur single-family home to a duplex?

• Not automatically. It depends on zoning, lot standards, sewer availability, and whether a historic or other overlay applies. Confirm jurisdiction and ask planning staff about two-unit allowances before you proceed.

How long does the approval and construction process take?

• A straightforward conversion often runs 4 to 9 months from concept to certificate of occupancy. Historic reviews or needed variances can add several months.

How many parking spaces will I need for a duplex?

• Many residential districts expect 1 to 2 off-street spaces per unit. Tandem layouts may count, and sites near MARTA or Decatur Square may justify fewer spaces, subject to local approval.

What financing options exist if I plan to live in one unit?

• FHA and conventional lenders offer programs for 2 to 4 unit owner-occupied properties. Start with HUD’s Single Family overview and speak with a mortgage pro about limits and occupancy rules.

Do historic districts allow exterior changes for conversions?

• Often yes, with review. Exterior changes typically require approval to ensure compatibility with historic character. Interior reconfigurations may be simpler but confirm early.

Will my property taxes increase after conversion?

• Likely. Adding a dwelling unit or creating income potential can increase assessed value. Check with the county tax assessor and plan for a higher bill.