Do I need a permit for addition or structural alteration in Unincorporated DeKalb County?

Yes. In Georgia, addition or structural alteration generally requires a permit, and Unincorporated DeKalb County is no exception.

Additions and any change to load-bearing walls require a permit and reviewed plans in Georgia; removing or altering a bearing wall usually needs engineered details. Additions may trigger energy-code, zoning, and setback review, so confirm the full scope before starting. DeKalb County's own permitting office is the DeKalb County Planning and Sustainability, reachable on 404-371-2155 at https://dekalbcountyga.gov/departments/planning-and-sustainability/permits-plan-review-and-inspections. Its online permit portal is https://epermits.dekalbcountyga.gov/. It issues permits for the unincorporated county. If your city does not run its own building department, and many smaller Georgia municipalities do not, this is the office that will handle the job. DeKalb County sits inside the Metropolitan North Georgia Water Planning District, created by the Georgia General Assembly in 2001. Every local government in the District, cities included, has to adopt the District's model post-construction stormwater ordinance or an equivalent one at least as effective, so these rules follow you into any city in the county rather than stopping at the unincorporated line. An addition adds roof area, which counts as impervious surface, and a large one combined with new driveway or patio work can reach the local threshold. In practice the thresholds are aimed at larger development rather than ordinary homeowner work, so most single-family projects sit below them. Cobb County, for example, publishes its trigger as adding more than 5,000 square feet of impervious surface or disturbing more than an acre. Each local government sets its own figures, so check yours before assuming. Where it does apply, the current standard is to retain the first 1.0 inch of rainfall on the site to the maximum extent practicable, which usually means a detention or infiltration feature rather than just grading water to the street. DeKalb's Residential Additions Permit Guide routes plans through zoning review, overlay review where applicable, and Land Development engineering review for buffers and floodplain before the permit is issued. A second-story addition needs an engineer's letter from a Georgia licensed engineer, based on a site visit, showing the existing structure and foundation can carry the new load. Additions within 75 feet of a stream must comply with the DeKalb Stream Buffer Ordinance, and homes on septic need Board of Health authorization (404-508-7900) for any residential addition. Under local amendment Sec. 7-52(b)(2)(B), a sealed site plan or staking survey showing setbacks must be submitted at the footing or slab inspection before concrete is poured. Schedule inspections at 404-371-3010.