This websection focuses on one form of architectural subterranea, the Sidewalk Basement.
Sidewalk basements are utilitarian underground urban spaces. They were built in the 19th and early 20th centuries (and probably the 18th, too) to be used as storage space, coal bins, elevator shafts, and other uses. Some were designed as basement corridors, and related architectural subterranea include stairs from the sidewalk and windows and doors into basement shops.
They probably evolved from pre-industrial era bulkhead stairs and ground cellars. They are still being built, though now primarily as larger utility spaces for electrical transformers, heating and cooling units, and for utility access.
This researcher became interested in and investigated the sidewalk basements in my home town of Chillicothe, Ohio, for two reasons. I had heard vague tales of an Underground Railroad tunnel running thousands of feet under the main downtown street, connecting many commercial buildings in the downtown, and I was curious and brave (or foolish) enough to want to explore this phenomenon. There was also a "Streetscape" plan that called for new sidewalks in the central business district. Construction work on this was impending, and the plan called for destruction of about half of the sidewalk basements known and located by the engineers.
Most of my observing and recording of them took place during the summer and fall of 1988 while construction took place. After reviewing the Streetscape blueprints, I asked the proprietors of downtown buildings to allow me to check out their basements, and surprisingly, most let me. I mapped out as many as I could, and took black-and-white photos of many. I also photographed the aboveground clues to the existence of sidewalk basements.
The sidewalk basements I investigated are classifiable into two types by roof form: brick arch and stone slab. These may appear to be an earlier and later method of construction, but there is no chronology apparent. The earliest sidewalk basements I know of in Chillicothe date to the 1840s and they are both of arch and slab construction. Even in the 1870s both types were built, even in the same building.
The basements with a brick-arch roof are simpler in construction and appearance, with brick or stone walls rising into a transverse or parallel arch, always with a round vent or solid cover that resembles a manhole cover. The apex of the arch is about seven feet high, and they are never domed. The floor is usually dirt, enriched by coal dust, mold, cobwebs, skeletons of small animals, bottles, candy wrappers, rubbish, brick dust and other items.
Basements with a stone slab roof are less cramped because the brick walls rise to the level of the sidewalk and the roof and sidewalk is formed by a large stone slab, sometimes supported by sections of railroad rail. Circular vents sometime perforate the slabs, and steel doors are common. The floor is usually paved with brick.
Beware of stories of "Underground Railroad" tunnels in downtowns - they often refer to these mysterious, spooky and often sealed-off subterranean spaces that rarely connect unrelated buildings and never extend into the street beyond the sidewalk.
As observed in Chillicothe, Ohio and other towns I've visited. Items numbered in Illustration 2 (as continued from Architectural Subterranea).
Stone Slabs surviving as sidewalk pavement. These usually extend only 1/4 or 2/3 to the curb, and reveal the extent and size of the sidewalk basement beneath. The large slabs are laid perpendicular to the direction of the sidewalk. In Chillicothe and Ann Arbor, the stone is sandstone, used in the late 19th century. In Chillicothe in the 1840s, smaller square slabs were used.
This small sidewalk basement was evidenced by the limestone slab at the front door to this commercial shop. The extent of the stone equaled the size of the room underneath, little more than a storage closet.
Two other sidewalk basements. Again, the extent of the stones equaled the size of the rooms underneath.
"Manhole Cover" in sidewalk, two species:
Coal Chute Cover. Sometimes slightly larger than other manhole covers and sometimes with a pop-up handle. Usually close to building wall.
Sidewalk Basement Vent. Usually perforated and always a mystery for small children. Usually in the center of the sidewalk because most basements are arched. May also have been used as coal chute.
Glass "Sidewalk Lights." Round or square glass, about two inches diameter and about one inch thick, in a solid cast iron or steel frame. Often broken and filled or covered with cement. Always along the building's wall, often at the main doorway. Allowed light into sidewalk basement. Old glass has turned violet with decades of ultraviolet radiation. Now being revived in modern design; q.v. some entries in the separate hyperpages.
Double Steel Doors. Always very polished by shoes, dished by traffic and with a few holes rusted through. Also popular with small children. Framed by stone or steel frame. May have hand-crank elevator underneath.
Stairway Doors. Always along building wall. Sometimes wood door survives; when located in front of shop windows, sometimes low doors under widow display floor open for headroom. Sometimes opens to coal chute or ramp for wheelbarrow.
Filled-in Sidewalk Door or Stairway. Evidenced by surviving stone frame or seams in cement, or change in color and weathering of cement. If the former opening is long and runs along the wall, and remains of bolts or other mounts exist in the framing, it was likely an exterior stairway into the basement.
Abrupt Shift in Sidewalk Level. If the street has a slight slope, the sidewalk basements are level until the end of building, and then the sidewalk drops off to follow the slope. (e.g. Waverly)
Vent Grille. Covers a window well usually less then three feet deep that slopes or curves directly into basement. May be bar or grill covering it. (Not a sidewalk basement; rather a species of architectural subterranea.)
Sidewalk Contractor's Stamp. A fascinating piece of urban material culture. Usually dated and with contractor's name and city. Use apparently began about 1890s and still in use. (Though not evidence of a sidewalk basement.)
Utility Access Cover. Usually for gas, water, or electric, and usually close to curb. Probably just valves or a small chamber beneath.
Gas Valve Access Cover. If there are sidewalk basements, the gas meters are often in them and this allows exterior access to the pipe and meter. Some 20th-century concrete sidewalk basements are built just for gas meters and electrical transformers. (e.g. Kresge Building, Chillicothe, Ohio)
See next webpage.