Work has begun on the $200M transformation of a vacant, Class-B office building near Union Station to a mixed-use building with office, hotel and retail.

Office Properties Income Trust announced Thursday it began construction on the redevelopment of 20 Massachusetts Ave. NW, a project that will add three floors and bring new uses into the building. It is expected to deliver in 2023.

The redevelopment, for which it filed rezoning plans in May 2020, will increase the building's height from seven floors to 10 and increase its total size from 340K SF to 427K SF. It will also re-skin the building to add floor-to-ceiling windows and change its use from office-only to mixed-use.

The hotel component is planned to be a 271-room Royal Sonesta Hotel, the announcement said, and marketing materials show it is slated for floors one through six.

On floors seven through 10, the building is planned to have 184K SF of Class-A office space. The ground floor is planned to feature 14K SF of retail space, and the building will also have a 14,500 SF penthouse space with a conference center and outdoor terrace.

Previously, the office-only building housed U.S. Citizenship and Immigration Services, which relocated to a newly built headquarters in Prince George's County.

The building was owned by Government Properties Income Trust, which merged in 2018 with Select Income REIT to form Office Properties Income Trust. RMR Group manages its properties. JLL is handling the office and retail leasing for the project.

OPI said the project will cost roughly $200M, and it projects an 8% to 10% return on investment.

“Upon completion, 20 Mass will be a state-of-the-art mixed-use destination with premier office space,” OPI President Christopher Bilotto said in a release. “We believe the property’s distinctive office, hotel, retail and amenity spaces will attract an array of tenants and visitors to its core Capitol Hill location.”