To build a squirrel house, construct a four-sided rectangular structure with a slanted roof and a 3-inch entrance. Use a non-aromatic wood, because squirrels chew on fragrant woods, including outdoor-grade plywood.
- Measure and cut the wood
For the roof and bottom, use two 12-by-12-inch wood boards. For the four sides, measure the pieces on an 8-foot by 6- to 10-inch board. For the front and back sides, cut two pieces that are the width of the board and 17 inches tall on one side and 18 inches tall on the other side. For the front entrance, cut a 3-inch notch from the top slanted corner of one of the pieces. For the other two sides, cut one rectangle 17 inches tall and another 18 inches tall.
- Assemble the house
Screw the four sides together. Align the 17-inch side piece with the short edge of the front and back pieces, and attach the 18-inch piece to the long edges. Make sure the seams are as tight as possible, and fill any gaps with waterproof silicone caulk. Turn the house over, and position the bottom piece flush with the back side. Screw on the bottom, and drill small drains holes. Flip the house back over, and position the roof so that it overhangs the front side and is flush with the back. Fill screw holes, knots and cracks with the caulk.
- Make the bed
Fill half of the house with synthetic pillow fluff or dried moss from a craft store.