It is hard to overstate the effect of fire – more specifically, the fear of fire – on the development of building technology in the US in the second half of the nineteenth century. Through the 1860s, people in the US had, mostly, continued building as they always had. They built all-wood buildings and sometimes masonry-walled buildings with wood interiors. This pattern of construction made sense in the colonial and early-republic days, as wood was cheap (forests were always within reach) and few buildings were meant to be permanent. As the country grew and cities began approaching the levels of density of older cities in Europe, this attitude became a problem. There were any number of large-scale conflagrations but there were also an endless series of serious fires involving one or handful of buildings.
Descriptions of these fires are horrifying, for the obvious reasons. Descriptions of the buildings themselves are also often horrifying because of the lack of understanding of fire-prevention that they show. The Windsor Hotel, for example, was built in 1873 and burned down in 1899. It covered the full east block front of Fifth Avenue from 46th to 47th Streets, and was effectively all wood except for its exterior walls. There were some partial interior masonry walls, but they were discontinuous and therefore could not serve as firebreaks. The stairs were wood, in open wells. In short, once a fire got going, there was nothing to stop it and were were wide-open avenues for it to spread laterally and upwards.
Because we now live in a world with various levels of structural fire protection, it can be hard to understand the totality of destruction that building fires used to cause. The picture above shows the 1857 Potter Building the day after it burned in 1882. It had been five floors high and filled the lot. The fire lasted well under an hour (similar to the Windsor fire) and completely destroyed the all-wood interior of the building. It spread via the wood stairs in an open well, by jumping from window to window vertically, and via the wood elevator shaft being constructed at the time of the fire. The wood floors braced the brick exterior walls, and once the floors collapsed, the walls fell inwards, leaving just the debris pile in the photo.
This rapid destruction is what led to the development of fire-resistant construction, starting with heavy timber and then, in the 1870s, fire-protected iron and steel.
