"The Zoning Commission has come down with a ruling that changes the requirements for rear additions. The zoning change limits extending a house at 10 feet beyond its neighbors' back wall. If you wish to extend past the 10-foot limit, you can go through a special exception process through the Board of Zoning Adjustment (BZA).
You can view the details of the new requirements here, and an editorial by Greater Greater Washington has additional information. The ruling goes into effect Friday, April 28.
It is DCAR's understanding that the new rule was a clarification from the wholesale zoning rewrite. DCAR in the past has commented that any zoning regulations that relate to property expansion, such as pop-ups, must be fair and balanced, protecting homeowner property rights.
We previously submitted comments to Chairman Hood of the Zoning Commission on the entirety of the rewrite stating our stance on the matter. At this time, DCAR continues to closely monitor the issue.
If you have questions about administration of the proposal, contact the Zoning Administrator at DCRA at (202) 442-4400. If you want to submit a special exception request or change the regulation itself, you can contact the Office of Zoning at (202) 727-6311 or visit its website here. We also encourage you to engage with the Office of Planning on this, or other proposals that affect DC's changing landscape, at (202) 422-7600."