Genius Engineering: Mortise and Tenon Joints

Because the fireplace would burn wooden framing placed under or around it, the craftsmen building the Slave Quarters were forced to used an alternative. They used Mortise and Tenon joints across the floor in front of the fireplace. This is a type of strong joint in which a mortise, or cavity, is cut into a piece of the frame. Then, a tenon, also called a tongue or tang, is made to fit inside the mortise. The joint pictured above allowed the craftsmen to support the second story without wooden frames being too close to the fireplace.

Close-up view of the mortise and tenon joint

Another view of the joint

The tenon board running across the room