A shed and playhouse can be built using the exact same floor plan. What distinguishes the shed from the playhouse is the details: windows, finished walls, floor coverings and furniture turn a humdrum shed into The Three Bears' house, a medieval castle or the deck of a space cruiser. These directions will allow you to make an 8-by 8-foot shed or playhouse with a pitched, rolled rubber roof.
Dig a shed foundation 8 feet wide by 8 feet long by 6 inches deep. Frame area using 2-by-4-inch-by-8-foot lumber. Fill foundation frame with gravel and compact with water-filled lawn roller. Add more gravel if needed and compact again. Brush sand over gravel area and use a carpenter's level on a long board to level the base. Scrape the board across the frame to remove any excess sand above the foundation frame. Roll foundation again, adding sand if needed, and levelling one more time. Sprinkle foundation lightly with a hose until sand is wet, but do not allow water to pool. Add more sand and compact again, levelling with a board. Allow foundation to dry 2 to 3 days. If desired, pour a concrete foundation instead of using sand and gravel only. See Resources below for directions on making a concrete foundation.
Lay five 2-by-4-inch-by-8-foot lengths of lumber 2 feet apart, on their 2-inch-wide edges. Lay the 4-by-8-foot-by-1-inch plywood sheets across the floor joists. Make sure the corners are square with the joists and the floor is level. If it is not, use wooden shims between the plywood sheets and the joists to level the floor. Drill 1/8-inch-diameter pilot holes for screws along each joist, about 8 inches apart. Countersink all screw holes. Screw plywood to floor joists using 2-inch-long wood screws.
Place a 4-by-4-inch-by-8-foot-tall post on the four corners of the shed floor, flush with the outside corners of the shed platform. Use a plumb bob to assure that the posts are vertical at a 90-degree angle to the floor, and that a board placed across their tops is level. If they are not, recut the posts at a 90-degree angle using a mitre box and back saw. Cut away the minimum amount to square and level the posts. Drill 1/8-inch-diameter pilot holes through the posts and into the floor joists at a 45-degree angle. Countersink holes and screw posts to floor joists using 6-inch wood screws. Lay a 2-by-4-inch-by-8-foot length of framing lumber on its 4-inch sides, across the tops of the posts, mitring the corners to meet flush at a 45-degree angle. This will create the roof frame. Screw the frame into place using 6-inch wood screws.
Position vertical studs every 2 feet between the floor and the ceiling frame. Drill holes at each end of the studs at 45-degree angles through the stud and into the floor or the ceiling frame. Countersink holes and secure with 6-inch wood screws. Lay ceiling joists on their 2-inch sides, across the ceiling frame going the same direction as the floor joists. Secure with 6-inch wood screws.
Frame walls, doors and windows. Make doors and windows 2 feet or 4 feet wide. Screw plywood sheeting into place for outer walls using 2-inch wood screws after countersinking holes. Lay 2-by-12-inch-by-8-foot roof support on its 2-inch edge at a 90-degree angle to the ceiling joists. Mitre 2-by-4-inch-by-4-feet lumber to make roof supports, coming together at the peak at a 90-degree angle. Attach 3/4-inch plywood sheeting to roof. Cover roof with rolled rubber roofing. Paint shed, or use siding or shingles.
Finish inside shed to convert it to a playhouse. Run wiring for ceiling lights, wall outlets and light switches before finishing walls. Install rolled insulation if desired. Attach 1/2-inch-thick sheetrock to walls using 3/4-inch sheetrock screws. Tape joints and cover with joint compound. Sand and paint walls as desired. Finish windows and doors with desired hardware and glazing.