The original building (located on 16th street) was completed in 1908 by architects Carrere and Hastings for Andrew Carnegie (click the link for more projects by Carrere and Hastings featured on this blog). You can see the front facade in the first photograph of this post and the side elevation (on P street NW) below.Delano and Aldrich in 1938 (click the link for more projects by Delano and Aldrich featured on this blog). Part of this addition is the carriage drive and new entrance which is a streamlined version of the Carrere and Hasting's Classicism.
scagliola, a faux-finish which mimics the stone. The Carnegie just restored the scagliola finish to 8 of the columns last year and plan on doing the remaining 8 this next year -all part of the maintenance of an old building (or house!).
I hope if you're in the area you'll join us at the ICAA on our future tours!