Shed roof framing for a basic structure is not a very complicated project. A little knowledge of carpentry basics and simple geometry will go a long way when trying to frame a shed roof. Prefab truss systems are available, but they tend to be quite heavy and require some assistance to lift into place and install. This article will stick to basic piece-by-piece rafter construction and wood-framing techniques.
Step 1 - Learn Roofing Terms
Before you begin your shed roof framing, you need to understand a few common roofing terms.
Span - The measurement from the outside of one supporting wall to the outside of the other supporting wall.
Run - Half the distance of the span.
Rise - The height from the center of the span to the top of the roof.
Line length - The distance from the outside wall to the center point of the roof where you took the measurement for the rise.
Pitch - The slope or angle of the roof. For shed roof framing use a 1/3 or 1/4 pitch.
Once you know about these and before you start the project, check with your local building department for the necessary building permits and requirements for erecting your shed. Also, always follow proper safety measures when working around construction tools, ladders, and when climbing and working on the roof.
Step 2 - Install the Truss
The truss is the supporting beam that runs the length of the shed. The truss is the beam that one end of each rafter will attach to. It is attached at either end to a vertical support beam that is attached at one end to the front wall and the back wall at the other end.
Step 3 - Cut the Rafters
The length of the rafters for the shed roof framing needs to be one foot longer than the shed is wide from the truss to the outside supporting wall. With your circular saw, cut one end of the rafter at an angle that matches the angle of the pitch. Next, cut a notch in each rafter at each end so the rafter fits snugly onto the side wall. Cut each notch at exactly the same position for each rafter.
Step 4 - Install the Rafters
Work with one rafter at a time, set each rafter at the desired location along the truss and set the notched end over the side wall. Please note the rafters should be spaced at a distance of 16 inches OC (on center). This allows easier installation of the plywood sheeting to complete the roof. Drive a nail or nails into the rafter securing it to the truss and do the same at the notched end. For a stronger and more secure shed roof framing, install joist hangers under each rafter at the truss end for additional support. Add them at the notched end of the rafter as well.
Once you have finished, stand back and admire your work, knowing that you did the shed roof framing on your own.