The R&T’s current clubhouse was designed by William Symmes Richardson, a partner at McKim, Mead, and White. The facility was built on a parcel offered for lease by a member of the club, Robert Goelet. Richardson, who had primary design responsibility for Pennsylvania Station and the Hotel Pennsylvania, proposed an integrated Italian Renaissance style and his firm’s proposal was presented to the membership for approval in April 1916 In addition to offering its members more spacious amenities, the move to Park Avenue afforded more consistent natural light for the skylit playing courts, as well a generally more desirable location. Construction began on December 20, 1916 and was completed on September 7, 1918. The builder was Mark Edlitz, and the estimated cost was $500,000. The court tennis court construction was carried out by Joseph Bickley. Board of Directors at this time included financier Ogden Mills and sportsman Harry Payne Whitney. 

The resulting building is about 200 feet by 100 feet (30 m x 60 m) and five stories tall. The exterior is stone and brick over a structural steel frame. According to the original plans, the interior contained three dining rooms, a billiard room, library, lounge, gymnasium, four squash courts, two court tennis courts, and two racquets courts. Today, there are four international squash courts, one hardball squash doubles court, one racquets court, and two court tennis courts. 

Source – wikipedia