A truss for a gable roof on one side of your home, for example, might need to be 15 feet (4. 6 m) long and 4–6 feet (1. 2–1. 8 m) tall. The dimensions of your structure will determine the angles formed by the truss’s top and bottom beams, or “chords. ” On a relatively shallow roof, for instance, the upper and lower chords may meet at a 30-degree angle on each side. [2] X Research source In some cases, building codes may dictate the size requirements of a truss for a certain type of structure. Be sure to consult your local building codes before you begin drawing up plans for your truss.
A king post truss may be all you need if you’re looking to add some extra stability to a garden shed or gable roof.
When fashioning a Fink truss, the middle of the “W” will be at the center line of the triangle. Similarly, the points formed by the internal joists will connect at the midpoints on either side of the center line. [5] X Research source Due to the symmetrical simplicity of their design, Fink-style trusses can also make an attractive alternative to plainer styles for ornamental structures like gazebos and covered outdoor shelters.
The internal angles in a Howe truss are repeated at regular intervals. Both sides of a standard Howe truss, for example, might consist of joists forming opposing 90 and 60-degree angles. Because of their complex configuration, Howe trusses tend to be difficult to plan and assemble, and are most often reserved very large load-bearing structures. A Howe-style design will offer maximum reinforcement for multi-level structures, as well as those built from especially heavy materials. [7] X Research source
If possible, use a tape measure to double-check the floor’s length rather than simply relying on the recorded measurements listed in the building plan.
Overhanging chords are more of a stylistic feature than a practical one, and shouldn’t affect the overall stability of the truss.
Use a circular saw or skill saw to cut your plywood to the right size and shape. [11] X Research source Making your own plywood gusset plates will help you keep the overhead for your project low.
You can order steel gusset plates from companies that specialize in construction timber or steel-working supplies. Solid steel gusset plates cost quite a bit more than plywood ones, so make sure they fit into the budget you’ve set for your project.
If you’re drafting up your plans by hand, use a ruler to make sure that your lines are straight and the internal angles of the truss are accurately represented. You can find many helpful digital design programs for free or cheap online. [14] X Research source
If you’re not sure who the licensing authority for your area is, run a quick search for “construction licensing” plus the name of your city, state, or territory. The criteria used by your licensing department may differ depending on factors like zoning laws, geographical features, and weather patterns. For example, if you live in an area with heavy snowfall, your city will likely have strict requirements about the bearing strength of your new structure. [16] X Research source Building codes may not apply if you’re just constructing a truss for simple structures like a small tool shed.
Refer back to the plans you drew up to keep track of how long each piece of lumber needs to be. Use a triangle square to verify the angles at the edges of the top and bottom chords. Trusses for common structures like houses, carports, and gazebos are most often constructed using 2 in (5. 1 cm) x 4 in (10 cm) wooden boards.
To prevent the pieces from shifting, consider using a table clamp to hold them fast to your work surface. Always wear gloves and safety glasses to protect yourself from injury while operating a power saw. [19] X Research source
Study your plans closely to make sure you’re piecing the internal joists together in the correct configuration for the style you’ve chosen. Keep in mind that the angles formed by the internal joists will remain the same despite differences in the frame’s height or width. This is a good opportunity to visually confirm that each component has been cut to the correct size. If you encounter any mistakes, you may need to start over with a fresh piece of lumber.
For ease of application, look for glues that come in tubes similar to caulk guns. [22] X Research source Take your time to make sure everything is where it needs to be. With most adhesives, you’ll have a window of 10-15 minutes before the adhesive begins to set. This will allow you to reposition your components as needed.
If you’re working with plywood gusset plates, you can drill your screws directly through the plates themselves. Give the adhesive 1-2 minutes to bond before installing the screws. That way, the friction of the drill won’t cause the plates to slip out of place. Allow the adhesive to set overnight. The following day, your truss will be ready to add on to the structure it’s intended to support.
