13 Types Of Roof Truss – Technical Plan Of Construction Update 12/2021

types of roof truss

Roof trusses are a critical component of any roof system. They provide the skeleton for the roof, and they help make sure that your home is strong enough to withstand all kinds of extreme weather conditions. But there’s more to it than just providing strength.

There are many different types of truss designs out there which do everything from adding insulation to making roofs look better. And because they’re so important, you need to know what kind you have before you start planning a major renovation or repair project on your house.

Familiarize yourself with these 13 types of roof trusses and their various uses in order to understand how best you can use them in your own construction efforts!

How important is the roof truss?

A roof truss is the most basic form of framing for a building. It is typically used to span between two bearing walls or beams and support a load-bearing wall or deck above.

Roof trusses are assembled from engineered wood products, which may be solid sawn lumber, laminated veneer lumber (LVL), glued-laminated timber (glulam) or a composite material such as plywood with built in steel reinforcement(PCL).

The exterior surface of the roof sheathing provides weather protection and soffit boards provide ventilation to protect against moisture build up.

In order to assemble a roof truss one must first have an idea of what type they want and then find it on the internet either through pictures or an actual blueprint, then one must find the materials needed to build it.

They may need to get help from a professional in some cases and if they do not know what they are doing or have never built a roof truss before it is advised that they at least look up construction plans with instructions on how to put them together.

Main types of roof truss

1.Lattice Truss Configurations

Lattice Truss Configurations

Lattice trusses are referred to as being either open or closed. Closed lattice trusses have less area in their webbing for a given weight than open lattice and tend to be more rigid.

The most common type of roof truss is the closed-web, also called C channel or finger jointed, which provides a simple mechanism to join members and is thus often used in place of splicing.

They can be more difficult to erect than other truss types because the webbing must be kept tight while the ends are being bolted together.

Open lattice trisses are also referred to as “latticework truss”. They are characterized by the use of a large number of timber members to form a truss with high strength and stiffness, but light weight.

They make it possible to span long distances with relatively few timbers (which explains their popularity in roof framing) but they are also difficult and time-consuming to erect requiring special skills or tools for assembly.

Lattice trusses are used in almost all residential construction.

2.Triangle Truss Configurations

These are the most common types of roof trusses and consist of two vertical sides, a bottom chord and top chord. The center is braced with lumber or plywood pieces.They can be used for span lengths up to 20 feet (6 m).

This type of roof truss is not that load bearing but rather just used as a frame.

As well as being used as a frame it can be used for ornamentation purposes. The truss does not have to necessarily support the roof itself but may bear on small posts or beams.

They are effective because they allow light into the interior of a building and offer high visibility from exterior views. Roofs with multiple triangular trusses give a more interesting appearance than roofs with rectangular trusses.

They are used in both residential and commercial areas due to their low cost. They can be assembled easily by the consumer as is common for most modern buildings in order to save money on labor costs.

3.Gable Truss Configurations

Gable Truss Configurations

The gable type of roof truss is one that employs a single pair of rafters to one or two collar ties which join a ridge board at the apex. It is commonly used in barns, industrial buildings and utility structures where strength and simplicity are paramount considerations.

The only difference between this type and a “plank” truss is that the former employs a valley beam rather than solid sloping sides as in the latter. The roofs of smaller buildings are often constructed from single versions of the truss, without any need for intermediate support.

This roof type is commonly used today as well and is one of the simplest to construct out of wood. It is a very efficient use of wood and is normally one of the cheaper to construct.

4. Cross Truss Configurations

This type of roof truss is one in which four sets of rafters are placed at right angles to each other. The rafters of the upper set cross in the centre, and are supported by a pair of collar ties on each side. It is essentially an open web truss with all diagonals that meet at the apex.

Its most prevalent use currently is as a bridge truss in the form of four box members linked by pin joints at both ends. This form allows for the efficient construction of many long span bridges and viaducts.

The roofs of smaller buildings were often constructed from single versions of this type, without any need for intermediate support.

Before the advent of the iron frame, trusses were used in many different residential buildings owing to their strength and economy in use of materials. This type of roof is still used today with a recent example being the Selfridges building.

This was commonly done but normally only for larger warehouses / factories or industrial buildings because of its large span which would require a strong support structure to bear the weight.

5. Hip Roof Truss Configurations

Hip Roof Truss Configurations

The hip roof truss is one that employs a pair of rafters to one or two collar ties which join with the ridge board at the apex. There are many variations of it as well, but the type with sloping sides only is called a “plank” truss while those having beams on all four sides at either level or in the valley are called “skew” trusses.

It is commonly used in barns, industrial buildings and utility structures where strength and simplicity are paramount considerations; the only difference between this type of roof truss and a gable type is that the former employs a valley beam rather than solid sloping sides as in the latter. The roofs of smaller buildings are often constructed from single versions of the truss, without any need for intermediate support.

This roof type is commonly used today as well and is one of the simplest to construct out of wood. It is a very efficient use of wood and is normally one of the cheaper to construct.

It largely superseded the older “church-type” trusses which employed king posts and arches to support the ridge. The hip roof did not require this additional construction technique and was thus cheaper to construct as well as easier and faster to erect.

This type of roof can be seen in many structures from large warehouses / factories, barns, and small stores all built during the early days of industrialization.

6.Parallel Truss Configurations

The parallel truss is one in which two sets of rafters are placed at right angles to each other. Each rafter pairs with a collar tie and the assembly rests upon the apex. The entire roof structure is supported by a pair of ridge beams, usually made of wood or iron.

It is essentially an open web truss, but with all the diagonals meeting at the apex. This type is also called a “Fan” roof from the shape of its rafters, which resemble fans or pennants when viewed from above.

This type of roof truss is one in which two sets of rafters are placed at a 45 degree angle to each other. Each rafter pair meets with a collar tie and the assembly rests upon the apex. The entire roof structure is supported by a single ridge beam, usually made of wood or iron. It is an open web truss with all the diagonals meeting at the apex.

This is the most commonly used type of roof truss at present. Typically, this structure employs a pair of rafters to support every other collar tie and thus creates an equilateral triangle at each intersection. The entire roof structure is supported by four ridge beams, normally made of wood or iron. It is a closed web truss with all diagonals meeting at the apex.

7.Trussed Rafter Configurations

The trussed rafter is one in which two sets of rafters are placed at 45 degree angles to each other, with a row of purlins holding them securely in place. The trusses rest upon the apex, and are supported by a single ridge beam.

This type was often used on houses built during the Industrial Revolution when there were a greater number of builders with less experience at using complex roof trusses.

This type of roof is often used on buildings such as churches and cathedrals, as it would have been built by highly skilled workmen who had no trouble with this fairly straightforward design.

8. King Post Truss Configurations

King Post Truss Configurations

A king post truss is a type of roof truss that consists of two horizontal beams and one vertical beam which goes from the peak of the building to the bottom corner of the building .

A king post truss is constructed by placing a pair of king posts into holes at the ridge which are then secured with iron straps. The two horizontal beams, resting on top of these king posts, are similar in appearance to purlins. They rest upon the apex and are supported by a single central column or kingpost.

This type of roof truss was occasionally used for longhouses but became more widespread with the use of wood-framed buildings in colonial America. It is also known as a “Latin Cross” because of its similarity to the Christian cross.

9.Cantilever Truss Configurations

The cantilever truss is a type that sits on top of the apex and is supported by posts spaced evenly along its length. The posts can be placed at either end or in the center of the roof and additional support may also be added using purlins.

This type of roof is very similar to the king post truss, with the main difference being that it supports a greater weight and has much more rigidity.

10. Trussed Rafter Overhang Configurations

A trussed rafter overhang describes any roof that uses more than 4 pairs of trussed rafters oriented at 45 degree angles to each other. The extra pairs of rafters are supported by purlins and also have a low-angled extension added that provides further support to the edge of the roof.

This type is commonly used on churches or cathedrals, where there is need for greater height in the building without making it any taller.

This type is similar to a trussed rafter overhang, except that it uses only two pairs of rafters and has the lower angled extension either missing or perpendicular to one side. This kind was used mostly on houses built in the modern world, when there was less need for a high roof pitch.

11. Gambrel Truss Configurations

Gambrel Truss Configurations

The gambrel truss is a variant upon the cantilever truss, with the posts in the center of the roof each being made longer so that they can be placed farther apart. This means there are no purlins needed to support them and it results in a greater clearance between posts at ground level.

This type of roof has a very steep angle, making it useful for warehouses or barns. The lack of purlins and the large size of the posts make this type much easier to create than other truss designs.

12.Hallow Roof Truss Configurations

The hallow roof truss is one that employs a single pair of rafters, which are supported at their ends only by either collar ties or wall posts and which join with the ridge board at the apex.

This type of roof is usually made from wood, but can also be composed of steel. It is often used in modern houses with flat roofs and no truss design.

13.Tubular Truss Configurations

The tubular roof truss is one that rests upon the apex and is supported by posts placed evenly along its length. They are usually held in place with iron straps or similar metalwork.

This type of truss has only two main components: one single horizontal beam resting on top of the posts and one long vertical post which supports both ends.

The tubular roof truss is similar to the king post truss, except that it has no horizontal beams and is made from wood . It can support a greater weight than the king post as it is one solid metal pipe rather than two beams resting on top of each other.

FAQs

– What are roof trusses?

A roof truss is a framework of wood, metal or other materials that supports the weight of a roof. It consists of two parallel, vertical posts with the horizontal beams, spaced accordingly and resting on top of these king posts. The two horizontal beams, resting on top of these king posts, are similar in appearance to purlins.

– When were roofs trussed first used in building construction?

Roof trusses were first used in the construction of houses with steeply pitched roofs to support the weight using a single king post. Before this point, buildings used arches or solid timbers to support their roofs.

– What is a common truss design?

A common truss design is the queen post, which supports a smaller load and has less rigidity than other designs.

– What is a king post truss design?

A king post truss design prop up the rafters and walls of the roof with two large posts. This type of roof structure is useful for buildings that need to have taller ceilings without adding more height to the building itself.

– What is the main purpose of a roof truss?

The main purpose of a roof truss is to support the rafter, purlin and ceiling joist. It also transfers loads from the walls in which it rests down onto its king posts.

Conclusion

Roof trusses are one of the most common structural elements in a building, and have been used for centuries. They can be made from wood or steel materials. Almost every type has some use that is beneficial to builders, but it’s important to choose which kind will work best with your needs before beginning construction on your own roofline project.

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