I am vague about who B. H. Warder was. He is called a "substantial citizen" in the book "Ups and Downs of an Army Officer" By George Augustus Armes, published 1900 by Harvard University. His wife and daughter turn up in some 20th century "social news" from news archives.

He had Washington DC architect Nicholas T. Haller design "The Warder Building" at the 800 block of F Street in Washington DC, Northwest, which was completed in 1892. Haller himself used the location for his DC office.

The building sold at $319 million in 2005 (Washington Business Journal brief newsbit about this here.) It states the building has 560,000 square feet.