How to Frame the Roof and Side Wall on a Shed

Frame walls first, using standard 8-foot studs, which actually are 92-5/8 inches long to make an 8-foot wall with the two plates. Build a wall on a level surface, such as the shed floor or a driveway. Use 16-inch spacing on stud centers; most codes allow 24-inch spacing on sheds but the lumber savings are minimal and 16-inch studs are stronger.

Size wall plates to the shed dimensions, allowing for wall connections. For an 8-by-10-foot shed, for instance, make end walls exactly 8 feet, but side walls 9 feet 5 inches, which will form a 10-foot wall when tied to the end walls. Measure two boards to the correct length and cut them with a circular saw.

Set wall plates together with 2-inch edges facing up. Measure 1-1/2 inches in from one end with a tape measure and use a speed square to draw a line with a pencil across both plates, to mark the first stud location. Measure 15-1/4 inches in and draw another line to mark the outside of the second stud. Measure 16-inch increments, based on that line, to the end of the wall.

Nail studs through the plates at marked spots with 16d framing nails and a hammer, two nails into each end of each stud. Nail the two end studs first to form a basic wall rectangle, then add interior studs. Use the speed square to make sure studs are square.

Frame a basic gable shed roof by making collar tie trusses, with two rafters from a peak to outside walls and a horizontal chord or brace between the rafters a third of the way between the peak and the wall top line. Make gussets of 1/2-inch plywood to fasten the joints. Cut these with a circular saw. Make the top gusset with a straight bottom to extend across both rafters and a top angled to the slope of the rafters. Make rectangular gussets to fasten the tie ends.

Use a framing square to cut truss rafters. Lay a 2-by-4 on a flat surface with the 4-inch face up. Put the point of a framing square at the bottom of one end of the board. Put the inch mark on the thin tongue for the roof pitch, such as 4-inch for a roof sloping 4 inches per foot, and the 12-inch mark on the wide blade at the top of the board. Mark that angle at the end for a top or peak cut.

Figure the length of rafter needed from a table on the square's blade. Look under the pitch mark to find the differential in length needed. Under the 4-inch mark, for example, that will be 12.65, meaning each rafter must be 12.65 inches long for every foot of run or distance between peak and wall.

Multiply that differential times the rafter run, which is half the width of the roof -- 4 feet for an 8-foot wide shed, for instance. Round off that total -- it comes to 50.6 inches so make it 50-1/2 inches. Cut a triangle birdsmouth to fit on top of the wall by drawing a 1-inch vertical line into the rafter at that distance and connecting if to a point 3-1/2 inches back up the rafter from the bottom of that line.

Add an overhang, typically a foot, and figure another angle, the reverse of the top cut. Calculate it the same way but with the point of the square at the top of the board. Cut those angles with a circular saw and use that pattern to mark and cut all rafters, two for each location 24 inches apart the length of the roof.

Lay rafters on a flat surface with tops butted together. Measure a third of the way down from the peak on each side and mark a line across each rafter at that point. Lay a 2-by-4 across the rafters and mark each end with an angle to conform to the slope, to fit inside the rafters. Cut those angles and lay this collar tie between the rafters.

Secure all the joints with gussets, using 2-inch galvanized screws and a screw gun. Drive two screws into the rafter and two in the tie, on each side. Turn the truss over and add identical gussets on the other side, taking care to make sure screws do not line up and conflict. Build all necessary trusses.

Set trusses in place 24 inches apart on the shed roof. Fasten each truss rafter to the wall with three 16d nails driven diagonally through the rafter into the cap board. Put two nails on one side, one on the other on each rafter end. Make sure the birdsmouth triangles are firmly on top of the wall cap before securing.