It's not all just wood and rocks for The Builder. They are also responsible for building and maintaining the farms that grow the essential food to help the Dwarven city grow.
All the classes are dependent on food to grow and The Builder needs to keep the stock up for to keep the hard working Builders, Warriors and Miners hard at work to keep the city safe and productive!
Actually ... at one point, The Builder can build a house where they can cultivate an advanced Farmer - any guesses on what type of house this could be?
https://store.steampowered.com/app/977650/DwarfHeim/