Washington DC is full of obsolete government buildings. See how one is being transformed into hundreds of luxury apartments.

• Washington, DC, leads the nation in office-to-apartment conversions, with 5,820 planned for 2024.
• The Cotton Annex, a landmarked federal building, is one of the latest to be transformed.
• It is now a luxury rental building called Annex on 12th, and residents move in next month. Take a look.

Washington DC leads the US in planned office-to-apartment conversion, with 5,820 developments planned in 2024 — an 88% increase over the previous year, according to apartment-search website RentCafe.

The Cotton Annex building, built in 1937 just half a mile from the Washington Monument, is one of them. Its original and only tenant, the US Department of Agriculture, left the building in the early 2000s.

The US government has an independent agency, the Public Buildings Reform Board, that sells valuable but underutilized buildings, like the Cotton Annex. “The status quo of nearly empty federal buildings is not financially or politically sustainable,” the board wrote in a March 24 report to Congress.

The government auctioned off the Cotton Annex in 2017. In 2021, developer Carmel Partners bought it from that buyer for $45 million. Now, after a three-year renovation that converted the space into 562 residential units starting at $1,637 a month in rent, it’s a place Washingtonians can call home.

The revamped building, called Annex on 12th, has the amenities typical for a luxury rental, like a rooftop lounge and a dedicated yoga space and spin studio. It also reinvented some features of the original building for a modern audience: The building’s residents-only speakeasy features the original skylight once used to inspect cotton.

Read on to see how the Cotton Annex was built and how it’s being transformed.