San Francisco Brick Company
San Francisco red brick in the remaining wall of the kiln on States St., San Francisco.
The San Francisco Brick Company opened for business in 1900 at 228 Montgomery Street in San Francisco, California.
It was incorporated in May 1898, with a capital stock of $500,000. This company was run by George F. Gray,
president, and Harry N. Gray, secretary, otherwise known as the Gray Brothers. The company owned about five
acres of land bounded by 16th (States) Street, Park Hill Avenue, Tilden (15th) Street, and Flint Street, near
Buena Vista Park in San Francisco. Loam, clay, and shale were mined from a pit on top of the hill.
The shale brick was suitable for structural purposes such as foundations, sewers, and tunnel-linings.
The brickyard and kilns were located on States Street. A large building, 350 feet long by 80 feet wide,
contained the engines, boilers, and kilns. The machinery included a 350-h.p. Risdon Corliss Engine, a 150-h.p.
engine, a 25 h.p. engine, 2 80-h.p. tubular boilers, 3 125-h.p. Babcock & Wilcox boilers, 6 oil feed
steam pumps, 3 steam boiler feed pumps, 4 elevators, a conveyor from the smaller to the larger mill, and
4 extension elevator belts with buckets. There were 3 water tanks, 2 steel oil storage tanks, a windmill,
and a well on the property.
The mined material was stored in clay bunkers with a capacity of 135,000 brick material. The material was
conveyed to 5 dry crushing pans and run through a No. 3 Gates crusher, with a capacity
of 150 to 200 cu. yds. per day. The crushed material was then passed through Elder Dunlap screens and
sent to the three pug mills, where the material was mixed with water to the right consistency. The clay
was conveyed to 2 brick machines, made by the American Clay Working Co., Bucyrus, Ohio. One had a capacity
of 100,000 to 125,000 brick per 10 hours, and the other of 30,000 to 40,000 per 10 hours. The extruded clay
was cut into bricks using a wire-cutting machine that cuts 20 brick simultaneously along the face of
the brick. Fancy pressed or paver bricks were conveyed on to the repress machine, which pressed the brick
under high pressure. Some of the bricks were conveyed to the cutting table for making hollow brick or
another cutting table for making hollow tiles. The wet bricks were stacked on drier cars or conveyors
and moved to the drying chamber on the second floor above the kilns. Waste heat from the kilns below dried
the wet bricks. After the bricks were sufficiently dried, workers stacked the bricks on railed cars and
these were rolled to the elevator to be lowered to the first floor. The bricks were stacked on the railed
car such that they could be easily rolled on rails directly into the kiln chambers without restacking.
The 28-compartment continuous oil-burning kiln was a 1901 patent design of George F. and Harry N. Gray and
Richard South. Each of the 28 chambers could hold 40,000 brick. The kiln had a
capacity of 140,000 to 150,000 bricks per day. These kilns fired the brick at temperatures
of 1,500 to 2,000 degrees F. Above the kiln was an enclosed chamber containing
a network of small pipes that conveyed the crude oil to the numerous apertures in the roof of the kiln
through which it was allowed to drip down into the combustion chamber below. These drips were regulated
by valves to control the heat. One large oil tank wagon was used to obtain the crude oil. Loss from broken
or defective brick was about one percent, and these were recycled through the plant again to
make new bricks. The plant employed about 53 workers.
The door of the kiln chamber was large enough to admit a brick wagon and team to be loaded after firing.
The finished brick were loaded into a patent dumping brick wagon. A pair of horses pulled the large brick
wagon to its destination in the city. The company in 1902 owned 11 of these brick wagons and 26 horses.
San Francisco bricks were used locally mainly in hospitals, schools, business buildings, and residences.
In 1905, machinery caused a fire at the brick works resulting in a loss of $15,000, though operations
continued. This was the only brick manufacturer in San Francisco during the time it was in operation.
The brick plant was closed by October 1914, when the firm declared bankruptcy.
Part of the wall of the 28-compartment kiln is still standing on the site, which displays some of
the brick probably made by this company. The tall single chimney, 160-feet high, a long time landmark, has
been razed with only the cement foundation remaining. The site is now a city park and partly covered by
residential homes. A couple of wood frame houses still standing on States Street served as homes for the brick
Three marked styles of bricks are known, but their chronology has yet to be worked out. One is stamped on the
face with SFBCo inside a deep rectangular frog and is the abbreviation of the brick company name. Another is
stamped on the face with GRAY inside a rectangular frog and named after the Gray Brothers, proprietors. A third
is stamped on the face with GRAY without the frog. The SFBCo brick is commonly seen as dark red to clinkery
black bricks in the buildings and homes in San Francisco.
San Francisco Brick
Common brick is orange, orange red, red, and dark red, mostly uniform in color. Visible angular
white quartz and gray chert up to 1/4-inch across, and small pits are displayed on the surface.
Sides are smooth with straight and even edges. Some surfaces appear to be granular, display small cracks,
lighter shades of flashing, and stack indentations. Corners often broken.
Slight velour texture on both top and bottom faces indicates cut by flywheel wire cutters. Grain
oriented longitudinal on both top and bottom faces, with minor transverse grooves present. No lip present.
The brick is hard and compact. Distinctly narrow in width. The brick displayed below in the wall of
a building in San Francisco, displayed the brand name "S F B C o" recessed inside a frog 1/8 inch deep,
6 1/2 inches long, and 2 3/8 inches wide. The block letters are 3/4 inch high, except for the little "o",
which is 1/2 inch high. The "S" was printed backwards. In the corners of the frog are four round screw
impressions 1/2 inch across. This brick was made using the extruded, stiff-mud process. Marked ones are
repressed. Length 7 7/8 - 8 1/4, width 3 1/2 - 4 1/8, height 2 3/8 - 2 3/4 inches.
San Francisco red brick bats. Bottom face view (upper left),
side view showing smooth extruded surface (upper right),
and side view with overburning and visible quartz clasts (bottom).
San Francisco dark red brick in a wall near the plant site.
Brand name "S F B C o" recessed inside a frog on a face of the
San Francisco brick.
Brand name "S F B C o" recessed inside a frog on a face of the
San Francisco brick. Note that the "S" is printed backwards.
Interior of a San Francisco brick showing white quartz, gray chert, and black iron.
Microscopic view of the interior clay body of the San
Francisco Brick Co. brick (50x, field of view is 1/4 inch).
Gray Pressed Brick
The Gray pressed brick is orange-red and mostly uniform in color. The surface is smooth with flatten
grains, small pits, and minor crackles. The edges are straight and dull. The corners are dull. The sides
may show transverse stack indentations. The faces display transverse grooves made by a blade or wire cutter.
There are two known styles of markings on one of the faces. One has recessed block letters spelled GRAY
that spans 2 5/8 inches in length and 3/4 inch in height on the flat face. The other has recessed block
letters of the same size inside a rectangular frog that is 6 3/4 inches long, 1 3/4 inches wide, 1/16 inch
deep. The brick spalls easily. The interior contains 15 percent subangular white quartz, red chert, subrounded red
sandstone, silvery mica schist, and grains of black iron, all ranging up to 1/4 inch across, in a red sandy
clay body. This brick was made using the extruded, stiff-mud process, and repressed. The size is slightly smaller
than the SFBCo variant. Length 7 3/4, width 3 3/4, height 2 inches.
View of the marked face of the GRAY pressed brick.
View of the side of the GRAY pressed brick.
View of the unmarked face of the GRAY pressed brick.
View of the marked face of the GRAY pressed brick with a rectangular frog. Collection of James Freedner.
Aubury, Lewis E., The Structural and Industrial Materials of California, California
State Mining Bureau Bulletin 38, 1906, p. 254.
Copyright © 2006 Dan Mosier
Brick and Clay Record, March 15, 1905, p. 39.
San Francisco Chronicle, November 12, 1914, p. 9.
Schuyler, James D., Report on the Brick Manufacturing Plant of the San Francisco Brick Co.,
10 February 1902 (copy in the Water Resources Library at U.C. Berkeley - Thank you
Bob Piwarzyk for sending me a copy of this one!).
Wolf, Jack J., pers. comm., 2006.