Cobb County, Georgia — one of the Atlanta metro's most populous counties — has a well-organized building and zoning department. For homeowners in unincorporated Cobb County, the key threshold to remember is 144 square feet for sheds. A 12×12 shed (144 sq ft) requires a permit; a 10×14 shed (140 sq ft) does not.
If you live in Marietta, Smyrna, Kennesaw, Austell, Acworth, or Powder Springs, contact your city's building department — city rules differ from county rules. The county's Community Development Agency at 1150 Powder Springs Street handles unincorporated Cobb County only.
Permit fees in Cobb County are based on project value. A shed permit typically costs $75–$175. Deck permits run $100–$250. Review times are generally 5–7 business days. Cobb County has an online portal at cobbcounty.org/CDA that accepts most residential permit applications.
What Requires a Permit
Frequently Asked Questions
- Yes. A 12×12 shed is exactly 144 square feet — at Cobb County's permit threshold. Cobb's rule is 'over 144 sq ft,' so a 12×12 falls at the threshold and technically requires a permit. To be safe, if your shed is 144 sq ft or larger, get a permit. Sheds under 144 sq ft (like a 10×14 at 140 sq ft) are exempt but must still meet setback requirements.
- Yes. Cobb County has an online permit portal at cobbcounty.org/CDA where most residential permits can be submitted electronically. You'll need to create an account, upload your site plan and any required drawings, and pay the fee online. For accessory structure permits like sheds, the online process is generally straightforward.