Shed trusses are no different in principle than other kinds of roof trusses. However, shed roof trusses, due to their much smaller size, require much less work, cost, and effort than building trusses for other applications.
A shed roof truss will normally be the most basic kind as well, so it is something that anyone with some familiarity of carpentry should be able to carry out. Each truss will consist of two rafters that support the roof.
The number of trusses you need solely depends on the weight of the roof, which, in turn, will depend on the length of the shed. A small shed will only need two trusses. The more trusses you have, the stronger the roof will be. After constructing the trusses, they can be hoisted up onto the roof and installed.
Step 1 - Make Preparations
Determine the amount of materials that you need to build the required number of trusses. Assuming both sides of the roof will be the same length, it should be easy to calculate the quantity of wood that you need. Make sure you account for about 15% extra just in case.
Each truss will need a bottom chord and two rafters, as well as two diagonal bracers to be installed in the center. For larger trusses, you may need extra braces. Calculate the amount of timber you need, and multiply this by the number of trusses required.
Step 2 - Cut the Wood
Cut the two rafters of the roof, having a plum cut in each end. This is basically a 45-degree cut. Cut the bottom chord. This will have the bottom of the two rafters connected to it. Cut all of the wood for each truss before continuing. Group the parts together to save time later on.
Step 3 - Cut the Gussets
Gussets are triangular shapes of plywood that can be cut using a jigsaw. The gussets will be used to attach each section of the truss. Gussets are always used in roofing to provide a very strong and durable connection. They can be made from steel or another kind of metal. However, for a garden shed, making the gussets from thin sheets of plywood is perfectly adequate and much cheaper. You will need to cut six gussets for each side of a truss.
Step 4 - Assemble the Truss
Build the truss on a level area of the ground once you have all of the required parts cut to length, including the gussets. You will need someone to help you with this, especially if each truss is fairly large.
Attach all of the sections together, starting by attaching the two rafters onto the bottom chord. Attach the two diagonal braces inside the truss, and glue everything together at the ends.
As the glue starts to adhere, attach the gussets over the joints, finishing one side of the truss before turning it over and completing the other. The gussets should initially be attached with wood glue and then nailed onto the beams for extra stability.