Mohr’s Subdivision in Sunnyside

From 1920 to 1923, Rudolph Mohr built one hundred houses in western Sunnyside, making it the first major housing development in the district since its founding in 1891. The project was notable for employing architects and techniques that set the houses apart from previous house-building in the neighborhood, which had been up until then largely one-off homes built by individual builders. The results were solidly built homes with attractive features, most detached, and many of which are still distinctive and in good condition today.

A Founder of the Neighborhood

Rudolph Mohr (1853-1928) was a intrinsic part of the establishment of Sunnyside by the Sunnyside Land Company in 1891. The company was led by Behrend Joost as president. Mohr served as secretary, but he turned out to be an abler business manager and a more methodical and disciplined planner. Joost got himself in to lots of trouble building his electric streetcar franchise then, and ended up disgraced, losing control of that pioneering but poorly run project. Mohr stayed in the real estate and building business long after Joost bailed out. Three decades after the founding of Sunnyside, Mohr was ready to leave a substantial and beneficial mark on the district by building good houses and selling them at a reasonable price.

This Research Project

I am embarking upon a thoroughgoing account of the Mohr development presently (Oct 2020), a project I began a few years ago. Over the next two years, in anticipation of the approaching centenary of the development, I aim to gather further documentation to fill out the story, including photos of original details and history about the Mohr family.

See this spreadsheet for a list of houses in Mohr’s Subdivision, with dates of contract, construction, or occupation.

See this page for a list of original features that may still be in these houses today.

Areas in western Sunnyside where Rudoplph Mohr and Sons built, Mohr's Subdivision in 1920s (pink) and prewar construction (yellow). Graphic by Amy O'Hair using Google Earth image.
Areas in western Sunnyside where Rudolph Mohr and Sons built: Mohr’s Subdivision in 1920s (pink) and prewar construction (yellow). Graphic by Amy O’Hair using Google Earth image.

The Prewar Years

Although Rudolph Mohr and Sons did most of their building from 1920 to 1923 in Sunnyside, there are 35 homes in the same area of western Sunnyside that they built from 1908 to 1913, before World War I. I am including these in the account, as they share characteristics with the 1920s homes: a uniform style, attention to details, an understanding of the importance of natural light, and methodical construction and sales techniques.

Mohr's Subdivision, Sunnyside History Project, San Francisco
Prewar house, Mohr’s Subdivision, Sunnyside, San Francisco

See this spreadsheet for a list of the Prewar houses. 

See this page for a list of original features that may still be in these houses today.

Innovation and Imitation

The 1920s saw a building boom all over the residential areas of the city. Adjacent to Sunnyside, Westwood Park (WP) began to be built in 1917. Mohr’s builder, James A Arnott & Son, employed stylistic details used on WP homes being built during the same years, enriching the interior and exteriors of the Mohr project. Yet Mohr’s houses cost more to build—$3700 versus $3000—attesting to the quality of material Mohr used.

Mohr also re-cut the lots on the blocks where he built, giving 30-foot frontages to the homes—five feet wider than the original 25-foot-wide lots. This allowed for the houses to be built as detached structures, as rarity in Sunnyside, where the 25-foot wide lot is nearly ubiquitous.

Mass building gave the houses similarities in size and positioning on the lots, while the variety of exterior details prevented a boring uniformity. Two floorplans, each also used flipped, giving four different layouts. Bulk buying of such things as front doors and interior features produced a savings in materials while, again, giving a stylistic coherence to the development.

In addition, beginning in August 1921, the previous firm hold that the building trades unions had on the construction industry in San Francisco was loosened.[1] Non-union labor began to be used on building sites, reducing costs.

Participation in the Project

If you live in Sunnyside and find that your house is one of those built by Rudolph Mohr and Sons in western Sunnyside, I would welcome hearing from you. If you have original details or features in the home that you would be willing to allow me to document, this would greatly enrich the final account of the development. In return I can provide you a printed binder of the final history.

Please contact me at

Check your address here:

  • Rudolph Mohr (1853 Hamburg, Germany – 1928 [at sea])
  • Rudolph Mohr Jr (1889 San Francisco – 1980 San Francisco)
  • Howard Emil Mohr (1891 San Francisco – 1958 Palo Alto)


  1. Frederick L Ryan, Industrial Relations in the San Francisco Building Trades, Norman: University of Oklahoma Press, 1936; and Michael Kazin, Barons of Labor: San Francisco Building Trades and Union Power in the Progressive Era, Urbana IL: University of Chicago Press, 1987.