How to Build Barn Roof Trusses

What You'll Need
Strong timber
Screws and power drill
Hammer and nails
Wood glue

Designing and building barn roof trusses can be difficult, even for somebody who is quite comfortable with basic DIY. The process is, however, no different to building roof trusses for any other kind of building, including a house. The trusses are one of the most important areas of the design of any roof, as they hold up the roof structure and have to be adequately strong to do so. The number of trusses that you need for the barn depends entirely on the length of the building. Trusses are not particularly complicated to construct compared to other parts of the roof, but this largely depends on the size of the building.

Step 1-Taking the Measurements

The first thing to do is take the measurements. You need to determine the pitch of the roof and the length of the rafters to figure out how much wood you are going to need. You may want to build a roof where one side is steeper than the other, but this can make matters little more complicated. You will then need to decide how many roof trusses you need. Make sure that you are going to have enough to support the whole roof for the length of the building. Double the number of trusses to get the number of rafters that you need to construct the trusses.

Step 2-Cutting the Wood

Each rafter should be cut from a 2x4 inch length of wood. The length you need entirely depends on the measurements you have taken for your particular roof. There should be a plumb cut in the top ends of each rafter. Cut the part of the truss at the bottom where the section connects to the two lower rafters. These are also cut from the same 2x4 parts of wood, but they are cut to 45 degree angles at each end.

Step 3-Building the Gussets

These need to be cut from half inch thick sections of plywood, although you can also use metal for sturdier results. These will need to cover the connecting areas of the trusses, such as the corners, bottom center and center of the rafters. You will need six of these for both sides of each truss. They need to be cut into triangular shapes and be long enough to connect the joints between each of the rafters.

Step 4-Putting Everything Together

For everything to attach securely and fit together as it should, the use of end blocks and stop blocks is necessary. They need to be screwed on to the side of the barn floor. Part of these blocks will reach up over the floor, securing the rafter to stop it from slipping off during installation. When these are in place, the truss can then be put in place, nailing the gussets into the corners.