To build a large dollhouse, cut a piece of plyboard into three equal-sized pieces to form the sides and center of the dollhouse, and cut a piece of plyboard to make the bottom of the dollhouse. Cut holes in the sides and center pieces to make doors and windows. Attach the sides and center to the bottom with screws and wood glue. Attach smaller boards to the sides and center to make the individual rooms, and attach the roof.
The side and center pieces should measure 23 3/4 x 73 inches, while the bottom piece should measure 23 2/3 x 48 inches. Cut the top of each piece at an angle to make a roof-shape. To make the windows and doors, outline the window or door on the wood, and drill holes around the outline. Use a jigsaw to cut the piece out.
When making the floors for each individual room, measure the space between the side and center pieces, and cut four pieces of plyboard to fit the space. Attach the floors with finishing nails and wood glue. Predrill the holes for the nails, and wipe away excess glue immediately.
Attach a piece of plyboard to the back of the dollhouse to make the roof. Frame the front of the roof or attic area with trim. Cut the trim to fit based on the dollhouse measurements.