For insulation and structural purposes, I wanted the wood structure to be 10cm thick in the walls and 12cm thick in the roof. But that means where the wall attaches to the roof, there is a corner with a surface of 10x12cm. Having a beam with a cross-section of 10x12cm would be overkill, and it would add extra weight that I don’t need. Plus, I have sections of the beam that need to be curved, and it would be very hard to curve a piece of wood that big. Therefore, I’ve decided to build a double beam made of two sections of 2.7x12cm, and put 5cm of insulation between the two sections, for a total thickness of 10cm. The curved parts I had cut out of 3-ply spruce by a CNC router. My first task for the caravan is to assemble these beams. I’m using my router to make an overlapping joint of 5cm between the curved and straight pieces.