The Park Avenue House is a 13-story brick and masonry building with Italian Renaissance details located on the northwest corner of Park Avenue and Montcalm. Since opening as the Royal Palm Hotel in 1925, it has been in continuous use as a residential building. Although the building has undergone alterations over the years, it is in excellent condition and still retains its original character as a downtown residential building.

The overall footprint of the building is rectangular, measuring ninety-two feet wide and eighty feet deep. The exterior façade material is orange brick on the east (front) and south elevations and yellow brick on the west (rear) and north elevations. On the front and south façades limestone is used at the base on the lower two floors and stone detailing appears on the upper two floors.

The structure exhibits the vast expanse of the plain wall surface of the skyscraper relieved with decorative Italian Renaissance detailing. The front elevation has a symmetrical façade composed of seven bays with double-hung wood sash windows.

Different window treatments emphasize the first, second, fourth, eleventh and twelfth floors. The second, fourth and sixth bays on the second floor have windows with rusticated stone surrounds with flat keystone arches that support a frieze with decorative festoons. The center window on the fourth floor has a console-supported stone balconet with an iron railing. The second, fourth and sixth bays on the eleventh floor have windows with iron railing balconets and rusticated stone surrounds with broken pediments that support windows with flat keystone surrounds on the twelfth floor. The building is crowned with a denticulated terra cotta cornice that has a line of stone lion heads in the cymatium. The lobby floor has a series of commercial metal recessed bay windows with large wood window boxes at sidewalk level and decorative street lamps between the bays. (These bays are a latter alteration and replaced the original storefronts).

The main lobby entrance is through an elaborate Renaissance arch doorway in the center of the front façade that has an arch flanked by rusticated pilasters supporting a Doric frieze. The frieze consists of triglyphs and metopes, and bears the name Royal Palm carved in stone in the center. The frieze supports a denticulated cornice. Double wood doors with a large single pane of glass sit under a semicircular fanlight in a decorative arch with festoons and keystone. On the second floor directly above the doorway the central windows are flanked by two feminine termini supported by an exaggerated reversed scrolled ancon. This assembly in turn supports the balustraded window balconet of the third floor center window. Two flag poles extend from shield-patterned supports flanking the second floor central window.

Architect Louis Kamper designed the Royal Palm Hotel in 1924 for Lew Tuller, a noted builder of hotels and apartment houses in Detroit. Among his other hotels were the Tuller on Grand Circus Park (built in 1906 and demolished in 1991), the Eddystone (opened in 1924) on Park Avenue, and the Park Avenue (opened in 1925 and demolished in 2015).

Louis Kamper came to Detroit from the offices of McKim, Mead & White in New York City and established his own office here in 1888. He was a devotee of the Italian Renaissance style, which he introduced to Detroit buildings in an attempt to combine monumental beauty with the commercial style. He was also responsible for the grand design and development of Washington Boulevard and most of its marquee buildings, including the Book-Cadillac Hotel and the Book Tower and Book Building for the Book brothers.

Tuller overbuilt in Detroit's hotel market. In 1928, he lost the three Park Avenue hotels in foreclosure and was forced into receivership by the Security Trust Co. In that same year, Security Trust sold the Royal Palm and the Eddystone to David P. Katz, a Detroit financier who made his wealth through hotels and extensive real estate transactions. He owned five Detroit hotels and one in Miami Beach, Fla. He retained the Royal Palm until 1966, when the discovery of a $2 million fraud against him caused the collapse of his business and his health. He died two years later.

In 1967, Wilbur Harrington purchased the hotel and renamed it the Park Avenue House (not to be confused with Tuller's Park Avenue Hotel). In 1990, he transferred ownership to Harrington Properties Inc. and his son, Sean Harrington, operated the building for the next three decades. The Town Pump, a neighborhood pub used to occupy the southern side of the building but has since moved across the street into the Iodent Building.