Decks, porches and roof decks in Washington, DC

The details

• Porches and decks, including alterations, always need a building permit.High confidence
• Uncovered decks no more than 4 ft above grade don't count toward lot occupancy. Since July 10, 2026 the first 200 sq ft of a deck off the main floor is excluded too.High confidence
• On row and semi-detached houses, a deck that counts as building area can't reach more than 10 ft past a neighbor's rear wall without a special exception.High confidence
• Roof decks need a building permit and structural review. In a historic district HPO checks whether railings are visible from the street.Medium confidence

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Common questions

What are the rules for decks, porches and roof decks in Washington?

Every deck and porch in DC needs a permit, including changes to existing ones. Low decks and the first 200 sq ft of a main-floor deck don't count toward lot occupancy.

Sources

1. DC Department of Buildings, How to get a permit. Checked 2026-10-20
   Unless you are in a historic district, the following work does not require a building permit: ... Replacement in-kind of ... Private sidewalks and driveways; Patios ... Single garden storage shed that does not exceed 50 square feet (4.65 m2) in area and is …
2. DC Zoning Regulations, RF zones (11 DCMR Subtitle E). Checked 2026-10-20
   RF-1: 35 ft height (40 ft by special exception); 60% lot occupancy for row dwellings, up to 70% by special exception; 20 ft rear yard; rear additions may not extend more than 10 ft past an adjoining building without a special exception (E § 207.5).
3. DC Office of Planning, Historic Preservation Office, permit review. Checked 2026-10-21
   [The Historic Preservation Review Board, staffed by HPO,] reviews construction affecting those properties [landmarks and properties in historic districts].