Find Inspiration for Your Vaulted Sidewalk Idea
Have you ever seen colored glass grids on a sidewalk when walking along a city street? Despite their lovely appearance, the patterns did serve a purpose – or at least they did at one point. The glass pieces are vault lights sidewalk, also known as pavement lights in the UK. They were inserted in the sidewalk to allow light into the basement below. Many of the glass pieces were clear when the lights were first installed. When the older glass was made, chemists mixed manganese dioxide during the process. This would stabilize the glass and eliminate the greenish tint it got from other elements. According to KQED, manganese turns purple or even pinkish over time as it is exposed to ultraviolet rays. Currently, colored glass is either very old or dyed to resemble old glass. Electricity became more common and cheaper in the 1930s, which diminished the use of vault lights. Due to the cracks in the glass, it created hazards for pedestrians as well as subterranean spaces below. As a result, cities began to cover or remove them. Some preservation groups, however, are seeking to restore the lights for their historic and aesthetic value. Several cities offer tours of vault lights and have studied their history and value.Design and Function
Usually, the tops of the vault lights are flat with the sidewalk, which allows people to walk right over them, but the bottoms often have a different shape.
The bottom of the glass block sidewalk lights has a prism design to spread as much light as possible across large areas. Instead of flat glass, prisms were used to diffuse the light evenly over a large area; flat glass would simply form a bright spot on the floor below, not providing much illumination.
The idea originated as deck lights in the 1840s. On ships, they were used to provide light below decks, especially when an open flame might be hazardous, such as on colliers. There are still deck lights made today, but few of the originals remain.
In the late 19th century, they were common in the larger downtowns, particularly in New York. As electric light became cheaper and better, their use declined, and by the 1930s they were on their way out. Today, designers and architects are trying to restore this old aesthetic.



