Look Down - Historic Streets

Feb 15, 20223 min read

In the 19th century, paving city streets was considered the most important civic improvement for the modernization of American cities, along with the installation of sewer systems. The earliest streets in Philadelphia were simply dirt roads. In dry periods, dirt streets generated dust, while with rain they could often become impassable.

In most cities, the first thing paved were sidewalks, often with wood planks, flagstones, or brick. Paved crosswalks, sometimes elevated above the level of the dirt roadway, formed the first stage in the process of paving the streets themselves. By the mid-19th century, cities began in earnest to start paving their streets. Philadelphia was actually a leader in paving streets, with much of the city paved by the 1830s. By 1884, the city had 535 miles of paved street, almost all cobblestone.

Cobblestones were the first material to be used in paving streets and roads. Most of the stones in Philadelphia were taken from the river beds of the Delaware and Schuylkill rivers. River rocks between 2" - 9" were washed, cleaned and assembled into sand beds.

Often coined “pebble paving,” the use of these stones lessened as traffic in the city increased. The pebbled streets slowed horse carriages and vehicles, and were too noisy to city dwellers. By 1916 almost all the cobblestones had been replaced with other paving material. Only seven streets are still paved with cobblestones, none of them original. (1st photo)

Cobblestone was largely replaced by Belgian block pavers and brick, which can still be found in many streets in Old City and elsewhere in the city. Belgian blocks or setts are a form of quarried stone, typically rectangular in shape, six to twelve inches in length and half that dimension wide. A Belgian block is defined by its shape, rather than its material, which is most often granite. Belgian block began to be used in the second half of the 19th century, especially on streets carrying heavy loads. (2nd, 3rd photos)

Many streets were paved in brick. (4th photo) Red vitrified bricks are fired at a higher temperature and for a longer time than conventional brick used in construction or for sidewalks, making them harder and waterproof. Yellow or orange vitrified brick was used on a few streets in the city (5th photo). Blueish glazed bricks contain iron slag and can be found on nine blocks, including under the covered walkway of Filbert St. between 2nd and 3rd St. (6th photo)

While asphalt paving was introduced in 1870, it did not become popular until the 1920's. Asphalt initially was a quite expensive and, being porous, absorbed horse urine and droppings, necessitating frequent street cleaning. With the rise of the automobile (and decline in horse drawn vehicles) and asphalt becoming less expensive, most new streets began to be paved with it. The majority of streets which were paved with Belgian block or brick were subsequently paved over with asphalt.

The previous paving can often only be seen when streets are milled in preparation for resurfacing. The old asphalt is stripped and recycled. Milling reveals a glimpse of the street’s former surfaces: a patchwork of old concrete, abandoned trolley tracks, Belgian block, and red brick. The historic layers see daylight for a few days or weeks, only to be paved over again. (7th photo)

Of the hundreds of miles of streets and roads in the city, only about 500 blocks on 150 or so different streets retain their historic paving material, with 68% being Belgian block and 25% brick.