Roof trusses are designed to spread the weight of the roof, and whatever lands on it, to the walls of the building. Just like a bridge truss would spread the weight of the cars and trucks crossing over it and transfers it to the piers.
What makes a truss more appealing to architects is the efficient and clever way it carries the heavy load. They tend to be lightweight as they take advantage of geometry and laws of statics.
Let’s take a look at the geometry…
If you imagine you have a set of flat popsicle sticks, and you drill holes at each end so you can connect the sticks with little bolts. If you connect three of these sticks together to form a triangle shape, you will create a structure which stays rigid even if the bolts are not that tight. If you made a square with the same method, it would slide to a rhombus shape unless you added a stick diagonally across the square (forming two triangles).
So, if you need a rigid structure, it is best to start with a triangle and build from here. This is very basically what a roof truss is!
Now let’s take a look at the laws of statics…
Trusses comprise assemblies of tension and compression elements (the extra sticks added across the triangle). Under gravity loads, the top and bottom chords of the truss provide the compression and tension resistance to the overall bending, and the bracing resists the shear forces.
What are the advantages of using roof trusses?
These are not the only advantages of using roof trusses over rafters. The other advantages include:
- Quality control in the factory. Because roof trusses are built off-site, usually in an indoor warehouse, their design and construction (saws and fabrication) are often aided by a computer. This means their design is consistent and controlled. Trusses may also be inspected and certified before they leave by a third party.
- Perfect timing arrival. You can choreograph the arrival time of the trusses to work with the building projects timescale. Meaning, they should arrive on time to be put up that day, so you will not need to store the materials.
- Quick construction. An entire roof can be trussed within a few days. Small trusses can be lifted by two or three people, so the job gets done quicker, saving labour costs.
If your build requires a reliable, cost-effective roofing structure contact the team at Aber Roof Truss today.
