What is a Roof Truss?

What is a Roof Truss? - Amazing Roof Restoration

A structural framework designed to provide support and strength to a roof, a truss is essential as the roof’s frame. They bridge the space above rooms and occur at regular intervals, held by longitudinal posts for support. Basically, they are triangular wooden structures designed to keep the integrity of a roof. You can usually find trusses supporting the roofs of airports, auditoriums, stadiums, stations, and theatres.

A roof truss is comprised of three main components: top chords, bottom chords, and web bracing. The framework consists of posts, struts, and rafters. The sizes of these parts are determined by load, spacing, and span. A truss is placed under compression and tension but is designed not to bend. It can also handle and sustain inclined, horizontal, and vertical loads. It will stand the test of time and provide a multitude of structural benefits to commercial and residential buildings.

Properties of a roof truss

Since they function as the roof’s main framework and reinforcement, they have to be incredibly stable and strong. Subsequently, they are built from wood or metal which means they can be custom-built and moved easily. Weight is distributed equally throughout the entire structure, so you can be sure your roof won’t fall in on your head.

A roof truss must be lightweight but steady. Compared to more traditional roof structures, they are much easier to assemble and transport from place to place. However, they require more labour to construct and maintain.

What is a Roof Truss? - Roof Truss

Importance of a roof truss

Because of the functions of a roof truss, they are the key to the integrity of a building. We all know that roofs are unquestionably important because they protect us from harmful outside elements. But without the support of a roof truss, they won’t be able to carry these functions:


A strong roof, supported with roof trusses, prevents harmful UV rays from the sun from entering the house. This applies to intense heat and weather as well. Allowing for a more comfortable ambiance inside your home. Heat won’t be able to enter, cooling down the temperature inside.

Protection and support

When a truss is installed, it helps prevent damage to the exposed roof. Since the roof is the first line of defence against the environmental elements, it must be reinforced further. Its main function is of course to cover and protect the home from exposure to sun and rain.

Types of roof trusses

Howe truss

Made of a combination of wood and metal, it is comprised of upper and lower parts. What’s notable about a Howe truss is that is has a wide coverage of 6 to 30 meters.

Fan truss

A fan truss is usually constructed from steel. It has a span of 10 to 15 metres and is one of the simpler roof trusses.

North light roof truss

This roof truss is notable as the oldest and most economical kind. It includes an extensive set of lattice girders with support posts. Commonly found in industrial structures and large spaces, it has a span of 20 to 30 metres.

King post truss

Made mainly for smaller-sized residential homes, a king post truss can span up to 8 metres. It is made of one central vertical post that uses tension to support a beam below the apex.

Queen post truss

Spanning around 10 metres, these are used in a wide array of buildings. It is considered to be one of the simpler trusses, but quite reliable and versatile.

Quadrangular roof truss

This is one of the more complex truss designs, found mostly in auditoriums and railway buildings. It is comprised of parallel chords and an arrangement of web members of tension diagonals as well as compression verticals.

Parallel chord roof truss

A parallel chord roof truss is made of two chords arranged parallel to each other with supporting posts in between. What’s advantageous about this truss is that is creates a vapour barrier, which helps lessen condensation and mould problems.

Pratt truss

With a span of 6 to 10 metres, this is the most economical and popular truss framework. It consists of vertical and diagonal posts that slope down towards the centre.

Raised heel roof truss

Useful due to its ability to improve the energy efficiency of a building, the raised heel roof truss is quite cost-effective. It is able to create ample attic ventilation and sufficient insulation for the walls of the house.

Scissor roof truss

These is used mainly in churches and cathedrals. The bottom chord posts of this truss cross each other and connect to the top chords at an angle. This has an appearance similar to an open pair of scissors, hence the name. The scissor roof truss offers support to vaulted ceilings with other standard trusses.

Where to find a trusted Newcastle roofer today

Looking for the perfect roof truss to use for your home? Contact Amazing Roof Restoration. We are a family-owned roof painting and repair business in Newcastle. With decades of experience and knowledgeable contractors, you’re sure to get the best value for your money with us! We specialise in residential and commercial roofing, using only outstanding, quality roofing materials. Contact us today for enquiries.