A 2x4 shed is built from 2-by-4-inch lumber and does not utilize larger lumber cuts such as 2x6s. These sheds are useful for the storage of yard and lawn equipment and can ease the crowding in a full garage. The shed is also easy to build for anyone with basic do-it-yourself skills.
Stake out the area for your shed; excavate area to a depth of 2 inches. Compact the soil firmly, add 2 inches of gravel. Lay out deck blocks into rows spaced 36 inches apart. Place the blocks every 16 inches on center within the rows.
Cut 2-by-4 rim joists and end joists to size for your shed's dimensions and fasten together with wood screws. Lift the fastened joists onto the outside deck blocks so that the edges of the lumber rest in the block notches. Measure and cut interior joists to size from 2-by-4 lumber, align between the rim and end joists in the notches of the deck blocks and nail into place at the rim joists.
Cut 5/8-inch plywood sheets for the floor of the shed. Nail plywood to joists.
Frame the walls to the shed by cutting three 2-by-4s to the size of the planned length of the wall to serve as bottom plates and a double top plate. Cut the wall studs from 2-by-4 lumber to a length that is the wall height minus 3 inches. Nail the studs between the top and bottom plates, 24 inches apart on center. Frame any needed openings into the wall for the shed's doors or windows.
Raise the walls into place; screw the bottom plates for each wall into the floor of the shed. Check that all of the walls are square and plumb; nail them together at the corners.
Raise the roof trusses into place one at a time, starting at the end, and nail to the double top plates. Space the trusses 24 inches apart on center. Cover the trusses with 5/8-inch plywood sheets to serve as the roof decking. Secure roofing felt to the plywood and shingle (use roofing tacks).
Cut 5/8-inch channel siding to the size of the outside of the walls; cut out openings to match those on the walls for the doors and windows, and nail the siding to the walls. Hang the doors and windows. Trim the shed, paint it, and your 2-by-4 shed is complete.