Rafters Versus Trusses

Homeowners often assume that a rafter and a roofing truss are the same thing. They do serve the same purpose and even look quite similar, but they are two distinctly different ways of framing a roof. Rafters have been used far longer in home building than trusses. Prior to the twentieth century, trusses were usually only seen in large construction projects such as churches or covered bridges. Both methods for supporting a roof have their advantages and disadvantages. While trusses are the more common method in modern home, Middlesex County roofers still use rafters in certain situations.

The primary difference between framing with rafters and trusses is the method of construction. Trusses are manufactured at a factory and shipped already assembled to the construction site where they are set in place. Rafters are cut and assembled on-site. The cut lengths of lumber are attached to a ridge board, which runs under the peak of a roof. To maintain shape and stability, a horizontal board, called a collar tie, is attached to the rafters connecting one slope to the other.

One of the downsides to using rafters is the cost of lumber involved. Rafters get their strength from the size and type of wood used. Rafter boards are generally 2′ x 8′ or 2′ x 10′.

Where trusses are assembled from 2′ x 4′ lumber and draw strength from the engineered design of their braces. Trusses can be set on a house much faster than rafters can once they arrive. Many times, this can be completed in a single day.

There are a few of advantages to using rafters in construction. First, they allow for a more open design beneath the roof than trusses. It is possible to create open space using trusses as well, but not to the same extent. The second advantage rafters offer is a shorter lead time. Trusses cannot be constructed without detailed engineer’s drawings. Once completed, they must be transported to the construction site. This is where the third advantage of rafter framing comes in. If the construction site is not easily accessible by an oversized semi-truck, then delivering the finished trusses can be a problem.

For small projects such as an addition or a shed, rafters will be the way to go. They do have their advantages and are still popular for their aesthetics in designs with exposed rafters. Homeowners can talk with their roofing contractor to learn which option best fits each project. The roofing experts at Fortified Roofing of Middlesex County NJ can answer your questions regarding new roofs or roof repairs.

Term explained by the roofing professionals at Fortified Roofing of Middlesex County NJ:

Roofing truss

A roofing truss is a wooden frame built to support the weight of a roof and span the area between load-bearing walls. Roofing trusses were developed in the middle ages but became more common with the development of the metal plates used to join the boards together.

Question and answer courtesy of the roofing experts from Middlesex County NJ at Fortified Roofing:

Which type of framing has the longest lifespan?

This depends on the construction. Either option should last as long as the house provided there is no damage to the member boards. Trusses are engineered to withstand specific loads and braced in more directions than rafters are. This gives them superior strength resisting lateral forces, such as wind. When installed by a competent roofing contractor either option will provide a secure base for the roof.

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