The triangular-shaped building's main architectural feature was the corner tower and dome, which resulted in the Portland Flats resembling an ocean liner sailing into Thomas Circle.

Apartment buildings had become a popular residential option in his native New York, and the trend continued in Washington, D.C., after completion of the Portland Flats.

Members of Congress often lamented the fact there were no acceptable places to rent with the $5,000 salary they received, and they often stayed in boardinghouses or hotels.

Weston was reluctant to invest a large amount of money in what was then a new trend in local housing, although he had witnessed the success and popularity of such apartment buildings in New York City and Chicago in the 1870s.

[4][7] Weston told a Post reporter that for the Portland Flats he would "spare no pains in its construction and will pay particular attention to interior decorations".

One real estate developer said "When the Portland was projected by Mr. Edward Weston he was laughed at, and it was said the people of Washington would never come to living in 'tenement' houses.

"[3] The six-story Renaissance Revival-style Portland Flats was built to accommodate the lot's triangular shape where 14th Street and Vermont Avenue intersect with Thomas Circle.

[2][3][4] The price and reputation of the Portland Flats led to its popularity with prominent citizens, and construction of the second phase of the building began after permit #0812 was issued on February 2, 1883.

In 1922 a fire broke out in Senator McKellar's fifth-floor apartment, quickly spreading to the sixth floor and roof.

[3][13] The following year the owners, who were relatives of Weston, sold the Portland Flats to local real estate developer Harry Wardman for $450,000.

Post architecture critic Wolf Von Eckardt commented on the demise of the Portland, which he called a "charming period piece" but also stated: "Inside, let's face it, it's a slum as well as a labyrinth and totally unsuitable as an office building."

[3] The site was used as a parking lot for a few years, including for people attending National City Christian Church across Thomas Circle, until an 11-story office building was constructed in 1968.

[4][18] Author and historian John DeFerrari said the shape of the Portland Flats was the "closest Washington has come to having its own Flatiron Building.

"[3] The red-brick, triangular-shaped building had six floors, not including the basement, and was designed in the Renaissance Revival style with intricate Victorian details including "decorative carvings, glazed brick accents, elaborate belt courses and balconies, and an unusually gaudy fifth floor cornice that appeared almost to drip with ornamentation".

Each apartment included a coal-burning fireplace in the parlor and dining room, mostly for aesthetic purposes, but steam heating was used throughout the building.

[4] The parlor fireplaces featured "rich ebony mantles, ornamental tile borders and hearths and are surmounted by beveled mirrors".

In addition to the lobby and parlor on the first floor, there were three public dining rooms, one of which was for women, a standard practice at the time of its construction.