What kind of wood is used for doll houses?

you can use 5 mil MDF (for walls and roof) which is better for cutting and shaping and does not leave slpintered edges when rubbed down. It takes paint well. Thin cut pine is good for doors and Windows, cills etc if you want a real wood effect else MDF all these as well. , Use a water proof glue at all times as this will cope with changes in moisture in the air aroudn the dolls house. If you are going to use the house for decorative purposes only then ply wood is good enough for the roof and walls.