Above, constructing a house in Boston in the lateish 1800s. The process of building the wood floors and brick walls was much the same everywhere rowhouses were constructed in the US.
Circa 1999, I found myself in Houston, reviewing the effect of constructing a large new office tower on two adjacent historic buildings. The small historic buildings were from the 1890s and consisted of wood joist floors supported on brick bearing walls. I said in my report that it was likely that a half inch of movement (if I recall correctly, it was expected that there would be a half inch of vertical settlement and three-eighths of inch horizontal movement towards the excavation) was likely to cause significant cracking in the walls of the two older buildings. That statement started a minor uproar in part because the local foundation engineer refused to believe me that the old brick walls were unreinforced. He thought I was saying that Texans were backward and wouldn’t follow recommended masonry practice, while my actual point was that in 1890 recommended practice did not include reinforcing in brick walls.
The following statements can all be true simultaneously:
- At any given time in a given place, there are a set of standards for how buildings are constructed. They may be informal or they may all have legal force from being in codes, but people constructing new buildings generally know what they are.
- Standards change over time, usually gradually but sometimes abruptly.
- Old standards that are no longer used are not necessarily dangerous or even wrong, but rather no longer fit with the general trend in current standards.
- There are always oddball buildings that don’t meet the common standards for their time and place.
There are two ways to address this issue. The first is to learn about old standards, which is a huge task. It’s easier to whittle that down by learning about old standards in your area and in the past decades that best represent the existing building stock. For example, there’s no great need for engineers working in New York to learn about seventeenth- or even eighteenth-century building practices here because so few of those buildings have survived; while learning about 1880 to 1900 rowhouses and tenements is incredibly useful because we have so many of those buildings. For a shortcut in New York, try here.
The second trick is to assume that any work on an existing building must be accompanied by some research on both its general type and on the physical artifact itself, on site. The general research may not be more complicated than remembering previous projects if you’ve spent a lot of time working on old buildings. The site investigation is generally understood but sometimes neglected.
The most important part of both learning old standards and researching a given building is to remember that it all made perfect sense to the people who built what you’re seeing now. Corollaries to that idea are that (a) what we do now in new buildings may look weird or wrong in the future and (b) if something doesn’t make sense in a building, try to see it from the perspective of the people who built it.