This is my first attempt at scratch-building. The walls are cardboard covered with a mixture of sand and wood-glue. The beams are balsa-wood and the thatching is from an old brush. The chimney is made of a core of self-hardening clay with small pebbles pressed in. I had a mayor problem with the walls, the cardboard warped considerably when I applied the sand-wood glue mixture. I now use foam-core for the walls of my buildings, it is more expensive but it is easy to work with and doesn't warp.