Image source Rafferty Roof Trusses
Roof trusses have overtaken rafters as the most popular way to create a roof frame. And there’s a good reason why trusses have become more popular - they’re cheaper, more convenient, and extremely versatile.
In this article, we break down what exactly roof trusses are and explain some of the most common types used in order to help you get insight into what kind of roof trusses you may want to use for your roof construction project.
On this page:
- What is a truss?
- Trusses are convenient and reliable
What is a roof truss?
Essentially, roof trusses create a roof’s frame. They determine the shape of the roof and ceiling while providing support for the roof. Trusses are pre-engineered in a factory using lightweight materials, like 2x4s, and are shipped to the construction site. Trusses consist of three main parts:
Bottom chords (also known as I-joists, or ceiling joists)
Trusses are used as an alternative to rafters, or stick framing. Rafters are usually made from larger pieces of lumber, such as 2x8s or 2x10s, and require the skill of an expert carpenter to custom-build and install them directly on the job site.
This makes rafters more expensive than trusses.
What are the advantages of roof trusses?
Roof trusses have become more popular than rafters in recent years for a few reasons. Perhaps the biggest reason trusses are more common is that they are over 30% cheaper than rafters.
They use lighter materials and are able to be produced and purchased in large quantities, driving down the price. The labor costs associated with trusses are also lower, as they don’t require the skilled labor of an expert carpenter. You can expect to spend anywhere between $50 to $450 per truss.
Another big advantage of truss systems is that they distribute the weight of the roof onto the exterior walls of the house, not the interior walls. With few to no interior load-bearing walls, home developers can easily create the wildly popular open-concept living spaces.
It also makes it easier for homeowners to take out interior walls in future renovations and home improvement projects.
Plus, there are countless truss designs to create the roof framing for almost any roof style. From gable roofing, to hip roof sections, there is a truss that will meet your needs.
Types of roof trusses
Again, there are a ton of trusses available to complete your building project. We’ve compiled a list of some of the most commonly used roof trusses for home construction.
King post truss
King post trusses are the simplest roofing truss.
Common uses: Home additions, garage construction, short-span projects
Span: 5 to 8 meters
King post trusses are the most basic type of truss. It uses the fewest truss members - two top chords, one bottom chord, a central vertical post called the king post, and two webbing chords.
Because king post trusses are made with few materials and a simple design, they come at a lower price point than many other trusses. However, this also means that king post trusses cannot span long distances, so they are better suited for smaller-scale projects.
Queen post truss
Queen post trusses are well-suited for larger residential projects.
Common uses: Residential home construction, home additions
Span: 8 to 12 meters
Queen post trusses are similar to king post trusses in that they have a simple, yet sturdy design. Instead of having one king post in the center, this type of truss will have two queen posts that are connected by a straining beam.
The additional posts in a queen post truss make them slightly more expensive than a king post truss.
The two vertical queen posts allow queen post trusses to span greater spans than king post trusses, which means they can be used for larger projects.
Fink trusses are the most common truss for residential projects.
Common uses: Residential home construction
Span: Up to 14 meters
Fink trusses are the most common truss seen in residential roof construction. The webbing in fink trusses has a ‘W’ shape, giving them a great load-carrying capacity. The position of the webbing allows for some storage space and can accommodate things like water tanks if need be.
They are also considered one of the most cost-effective roof trusses available, especially because they can span far distances.
Attic trusses allow for storage space and sometimes even added living space.
Common uses: Residential home construction projects that require an attic or additional loft living space
Span: Up to 25 meters
One downside to many trusses is that the webbing can often limit attic space. This can be a dealbreaker for homeowners looking for additional storage or living space. Luckily, there are attic trusses, which are built to allow for attic space.
Attic trusses look similar to queen post trusses, but the two vertical posts are spaced further apart to allow for attic space. The wider the building structure is, the bigger the attic space will be. The steeper the roof pitch is, the taller the attic ceiling will be.
Scissor trusses can create vaulted cathedral ceilings.
Common uses: Residential home construction projects that require vaulted ceilings
Span: Up to 22 meters
Scissor trusses make it possible to create vaulted ceilings. The bottom chords of scissor trusses are sloped, creating the dramatic ceiling in the room below. Scissor trusses combine the speed and convenience of using pre-engineered wood trusses, while still getting the aesthetic benefit of high ceilings.
You can install scissor trusts in one part of your home, and use other types of trusses in other areas of your home where you don’t want vaulted ceilings. What’s great is that from the outside, your roof will look uniform, even if one area has high ceilings.
Keep in mind that scissor trusses do come at a higher cost than other types of trusses - sometimes up to 30% more than standard truss types.
Gable trusses act as the ‘bookends’ to your roof.
Common uses: Residential gable roof construction
Span: Varies depending on roof design
Gable trusses are usually used in combination with other types of trusses. The gable truss serves as the ‘end cap’ for the roof. They have two top chords, one bottom chord, and multiple vertical posts. Gable trusses are built on each end of the roof framework to support roof sheathing.
Gable trusses will cost anywhere from 25% to 50% more than standard-style trusses.
Roof trusses are convenient and reliable
We’ve listed out six of the most common roof trusses, but there are many more types on the market. From metal roofs to asphalt shingles to vaulted ceilings and flat roofs, there is likely a truss that can help you get the job done.
Roof trusses are versatile, cost-effective, and convenient. Working with an experienced architect or structural engineer is the best way to guarantee that you’ll find the right trusses for your home and meet your building code requirements.