I was out in Fairfield County this weekend working on photographing a list of historic locations when the question came up, “Why build a covered bridge instead of a regular span?” It’s a great question and I honestly had no clue what the answer was and had to do a little research.
Think about it for a second. If you are building a covered bridge you are basically building a barn over a regular bridge span. It’s going to take more time, more resources, and cost more money. So what could justify it? The answer is longevity. A regular, open, wooden truss bridge had a life span of 8 to 10 years before the weather would take a toll on the wooden structure and you would be looking at a decent amount of repairs or an entire rebuild of the bridge. Engineers found out that if you built a structure around the bridge to protect it from the elements you could extend the life of the bridge structure to 70 or 80 years. Up keep was simple; if you could paint a barn you could paint a covered bridge.
So there you are, the short answer on why a covered bridge was better. Of course the advent of steel bridges changed everything but that’s a post for another day!