The Maze Runner Wiki
"Over there, we got the Builders. They're very good with their hands, but they're not a lot going on upstairs."
Newt to Thomas in the Maze Runner film

Builders are the ones who build most of the things around the Glade, such as structures and other simple items that would help with carrying and moving things around. They also upgrade existing structures and buildings as well as repairing them. The Keeper of the Builders is Gally.