Oak trusses are the perfect blend of architecture and engineering. Made from the strongest shape – the triangle – they support roofs across the country but they can also be a design feature in themselves.
If you have ever looked up while in your loft or driven past a house under construction you may well have seen a truss.
But do you know the history of this elegant construction tool, the options available and how they are created?
Here are four things you might not know about oak trusses.
Truss derives from the Old French word ‘trousse’, circa 1200, which roughly translates as a collection of things bound together.
Trusses bridge the space above a room and provide support for a roof.
Believed to be a Medieval development, they became more popular than traditional coupled rafters.
Coupled rafters were structurally weak due to a lack of longitudinal support and were prone to collapse.
In contrast, the typically triangular shape of trusses allowed them to span a large distance transmitting all the weight to exterior walls.
The triangle is the strongest load-bearing shape. This structural stability is why trusses are typically composed of triangles.
The simplest truss is one single triangle. It is most commonly seen in a framed roof with rafters and a ceiling joist.
It can also be see in other mechanical structures including bicycles and aircraft.
The bottom chord, or tie beam, is the base for the truss which houses the principal rafters and braces.
When you look at the structural mechanics of a truss, the principle rafters hold the tie beam up allowing the truss to take large amounts of weight when in compression.
The types of truss
Despite their apparent simplicity trusses come in hundreds of different configurations.
The three most popular are king post, queen post and collared.
A king post truss has two principal rafters, a tie beam and a central vertical king post. The simplest of trusses, it is commonly used with two angled struts.
Normally under tension, it requires sophisticated joints with the tie beam and principal rafters.
A queen post truss has two principal rafters and two vertical queen posts. This distinctive shape extends the useful span.
A collared truss has the tie beam much higher up on the principal rafters allowing for greater headroom from the truss. With collared trusses, it is usually the principal rafters that sit upon the walls as opposed to the tie beam.
The oak trusses we can create for you
At Tradoak we can make solid oak trusses to any specification set by a structural engineer or architect.
You can see an example of just one of our large raised collar trusses projects here.
To find out more or get a free quote visit our contact us page.