Looking at the 1920 census there were two African American households at 206 R St NW. One was the Lorenzo McClane family, the other was widow Lillian Sorrell and her two minor sons. In the census Mrs. Sorrell is listed as the owner. However, when I check the Recorder of Deeds, she is not listed. Instead the owner was Ellen Fanny Burden, who died in 1929.
Ellen F. Burden was an English born single woman who owned several lots on Sq. 551 with her sister Edith Burden Hastings.
Anywho, this was a dead end.