I was thinking, how long would it take to build a typical roman wall like the ones we find in the UK. I realize that it depends on how long it is. But was there usually more troops in the area when the building was done ? How did it work exactly ? Where was the material acquired ?
Thanks!
To answer your question I'm going to look at Hadrian's wall. Construction began in 122 AD and lasted six years. The wall stretched for 117.5 km and varied in height and width but was often 3 meters wide and 6 meters high. Along the wall every roman mile (1.48 km) there was a milecastle which housed a small garrison and gate. As for the construction force, it consisted of portions of the three roman legions that were occupying the isles. The main material used for Hadrian's wall was limestone and was sourced locally
To specifically answer your question it depends on a lot of factors, how many troops are in the area and available, what type or wall material is in the area. But looking at Hadrian wall we can determine that it would take 1 year to complete roughly 20 km of wall, including 13 mile castles.