You may think it doesn’t really matter what type of roof truss you choose since it’s just a part of your roofing system. But since there are many types of roof trusses, you’ll have to use the one most appropriate for your roof.
Additionally, there are different reasons to use a certain type of truss for a particular project. We have gathered a list of some of the most common types of roof trusses to arm you with the necessary knowledge for your next roofing venture.
What is a Roof Truss?
A roof truss is a prefabricated triangular framing that supports the weight of the roof. The triangular webbing of these pieces not only supports the roof but also ties the outside walls together. Trusses are typically made from wood, steel, or both and are bolted together to support the roof.
On average, roof trusses cost around $12,000, depending on the material and type of truss. Most trusses have the following parts:
- Top chord: This is the beam on the uppermost part of the truss.
- Bottom chord: This is the horizontal beam that defines the bottom part of the truss.
- Web bracing: These are beams that connect the top and bottom chords.
- Panel points: These points are where the web members intersect with the top and bottom chords.
- Heel: It is the point where the top chord and bottom chord meet at the ends of the truss.
- Peak (or ridge): It defines the highest point of the roof’s slope.
- King post: In some truss designs, particularly those with a central vertical support member, there may be a king post extending from the top chord to the bottom chord.
Types of Roof Trusses
1. King Post Truss
This type of truss uses the fewest truss members – two top chords, one bottom chord, and a vertical post in the center called the king post. It’s the simplest type of truss since it requires fewer materials, making it the most budget-friendly.
Common Uses of King Post Truss
- Smaller homes
- Home additions
- Garages
- Sheds
- Porches
Typical Materials Used for King Post Truss
- Cypress
- Glulam
- Reclaimed timber
Pros of King Post Truss
- Strong and stable
- Even load distribution
- Easy and economical
- Available in different shapes and roof angles
- More space for plumbing pipes and vents
Cons of King Post Truss
- Limited span and flexibility
- Not suitable for bigger projects or commercial buildings
- Can’t support heavier concrete or Ferrocrete roofs
2. Queen Post Truss
Similar to a king post, this truss has two posts extending from the center along with a king post. These are often found in new home construction projects or larger home additions.
A queen post truss will be slightly more expensive than a king post due to the additional materials necessary. However, they can be made with metal or steel to help lower manufacturing costs. A queen post is also sturdier, holds onto heavier roofs, and can cover larger areas.
Common Uses of Queen Post Truss
- Large homes
- Home additions
- Two-car garages
- Store rooms
- Warehouses
Typical Materials Used for Queen Post Truss
- Steel
- Yellow pine
- Teak
- Fir
Pros of Queen Post Truss
- Customizable
- Long span
- Better tension resistance
- Durable
- Long-lasting
Cons of Queen Post Truss
- Fixed structure and cannot be altered
- Costly and tedious to install
- Cannot have clerestory windows at the sides
3. Fink Truss
This is the most common roof truss used for residential roofs, especially for high-pitched roofs and those that have longer spans. The webbing on this truss forms a W shape that allows for a heavier load. It has excellent strength, versatility, and cost-effectiveness because of its ability to span bigger distances. Its webbing also allows for storage space and has fewer joints, helping create stability.
With this type of truss, you can choose from any of the following, depending on your project requirements:
- Double fink truss: It has an additional post that creates a W-shaped web, making it span more than 65% longer than a single fink truss.
- Fan roof truss: Often characterized by its fan-shaped webbing, this truss is used for a longer span roof that is too long for a king or queen post truss. Fan trusses also support the same amount of weight as other types of trusses but use less materials.
- Hip truss: Slants downward on all four sides and resembles a pyramid on a square building. These types of trusses offer stability and are often used in areas that often get high winds and snow.
Common Uses of Fink Truss
- Large span roofs
- Community halls
- 3-car garages
Typical Materials Used for Fink Truss
- Alloy steel
- Galvanized steel with zinc coating
Pros of Fink Truss
- Best for high-pitched roofs and column-less spaces
- Extremely affordable
- Easy to design
- Durable
- Smaller members
- Weather-resistant
Cons of Fink Truss
- Delicate
- Unsuitable for heavy concrete roofs
- Cannot be stacked easily
4. Attic Truss
This roof truss uses webbing to frame the walls of a room, making it easier to convert into a storage area or even a proper room. These types of trusses can really add value to your home as they leave space for lots of storage or potential for converting the space into a bedroom or home office.
If you’re looking for a taller attic ceiling, try using a steeper roof pitch; the steeper the roof, the taller the attic ceiling. A high-pitched roof or a wider roof also allows more natural light inside.
One downside to using this truss is it can be susceptible to fungus and has poor weather resilience. It may even decay from wall leakages and warp from moisture. So, it’s best to use an attic truss in sunny, dry, or windy areas.
Tip: To prevent fungus, use the right roof flashing, direct water away, and use a dehumidifier to dry the trusses during and after rain or snow storms.
Common Uses of Attic Truss
- Homes with attics or loft space
- Mezzanines
- High-pitched roofs
Typical Materials Used for Attic Truss
- Cedar
- Reclaimed wood
- Cypress
Pros of Attic Truss
- Compact and web-free
- More storage and headspace
- Better light and ventilation
- Greater span and pitch
Cons of Attic Truss
- Poor weather resistance
- Vulnerable to pests and bird nests
- Prone to leakage and fungus
5. Scissor Truss
With this type of truss, the bottom chord posts cross each other and connect to the top chord, creating an open scissor shape. A scissor roof truss is often used in homes with open-concept floor plans and vaulted ceilings.
You can mix and match scissor trusses with other types in different areas of your home. This can allow you to have vaulted ceilings in the main living area and lower ceilings for other rooms. These trusses can be up to 30% more expensive than standard truss types, as they require extra tie beams for support and protection against buckling from heavy roofs or snowfall.
Tip: Use thick, rigid foam insulation at the bottom of the truss to help melt snow, reducing the stress on the trusses.
Common Uses of Scissor Truss
- One-car garages
- Detached garages
- Small villas
Typical Materials Used for Scissor Truss
- Cedar
- TR-26 grade timber
- Reclaimed wood
Pros of Scissor Truss
- Clear headroom and space
- Better light and ventilation
- Wind resistant
Cons of Scissor Truss
- Lower compression strength
- Expensive
- Difficult to install
6. Gable Truss
This type of truss is used to form a pitched or peaked roof. Two top chords, a bottom chord, and posts that make up the webbing are the components of this truss. The webbing is a series of vertical posts spaced at intervals.
A gable roof truss is typically used along with other types of trusses and can act like a bookend on your roof. It’s designed to transfer vertical loads from the roof to load-bearing walls.
Common Uses of Gable Truss
- Residential homes
Typical Materials Used for Gable Truss
- Steel
- Engineered wood
Pros of Gable Truss
- Rain and snow-resistant
- Cost-effective
- Storage space
- Temperature control
- Versatile
Cons of Gable Truss
- Vulnerable to extreme weather
- Frequent repairs
- Not ideal for an extra room
7. Mansard Truss
This is a two-story truss with pitches from 30 to 40 degrees at the top and 60 to 70 degrees at the bottom. Mansard trusses have a king post at the top and two queen posts at the bottom.
This four-sided hip roof can add headroom and storage space. It can give your home a traditional look and is mostly used in barn houses. They can be difficult to assemble and will require a permit for installation.
Common Uses of Mansard Truss
- Two-story homes
Typical Materials Used for Mansard Truss
- Cypress
- Glulam beams
Pros of Mansard Truss
- Compact
- Allows for more headroom
- Heat and light distribution
- Economical in two-story homes
Cons of Mansard Truss
- Difficult to install, repair, and maintain
- Permit and taxation charges
- Poor weather resistance
8. Truncated Truss
These are trusses that look like they’ve had their hat chopped off, creating a flat-topped truss. It has a gentle slope on either side with parallel top and bottom chords with webbing that creates a W shape.
A truncated truss offers a clear space to accommodate a room while creating another buffer, offering better insulation and temperature control inside. However, you will want to use a thin, dry, or partition wall with a truncated truss. Don’t use brick or concrete blocks to line the room – it could place too much stress and break the truss.
Common Uses of Truncated Truss
- Low-rise homes
- Garages that need living space
Typical Materials Used for Truncated Truss
- Spruce
- Pine
- Cedar
Pros of Truncated Truss
- Lower construction costs
- Additional living space
- Better insulation
- Weather-resistant
- Durability
Cons of Truncated Truss
- Susceptible to pests and mildew
- Difficult to clean and maintain
- It might not work in heavy-rainfall areas
9. Belfast Truss
A Belfast truss has a curved top chord that meets the bottom chord at each end. It’s often used for modern homes with curvilinear roofs and also may be referred to as a latticed or bowstring truss.
It can support pendant lights, insulation, and false ceilings, but it isn’t able to accommodate skylights or roof vents. Consider using a dehumidifier or artificial air conditioning to help combat the heat and humidity created by a lack of roof vents.
Note: Since it’s likely to buckle under heavy snow, Belfast truss is best used in tropical or dry regions.
Common Uses of Belfast Truss
- Vaulted ceilings
- Garages
- Storerooms
Typical Materials Used for Belfast Truss
- Cypress
- Teak
- Fir
- Pine
Pros of Belfast Truss
- Finished and modern aesthetic
- Lightweight
- Easy to assemble
Cons of Belfast Truss
- Might fail under extreme weather conditions
- Increases energy costs
- Poor light and ventilation control
10. Girder Truss
Often used for traditional roofs, this type of truss can support traditional attics and dormers. It is a long, rectangular truss with saw-toothed webbing that helps to span longer distances. Girder trusses are often used as secondary roof support but may not support the weight of a modern steel roof.
They are often used in homes with irregularly shaped roofs and L- or T-shaped buildings. Girder trusses also can be used to provide structural support to the roof and adjoining walls. For this reason, they are a good choice for areas prone to hurricanes, tornadoes, or other powerful forces of Mother Nature.
Common Uses of Girder Truss
- Small homes
- Attics
- Sheds
- Vaulted ceilings
Typical Materials Used for Girder Truss
- Alloy steel
- Glulam beams
- Reclaimed timber
Pros of Girder Truss
- Durable
- No central supporting post or bracing is needed
- Customizable to linear and curvilinear roofs
- Provides clear attics
- More interior space
Cons of Girder Truss
- Heavy
- Difficult to install
- Needs specialized joints and fittings
- Average weather resistance
Benefits of a Roof Truss
- Sturdy: Trusses distribute weight evenly, providing a safe, sturdy frame that increases structural integrity. This also helps take the load off interior walls, leaving room for an open floor plan.
- Versatile: They can be custom-built to fit any design and can be scaled to fit any building. Whether you are planning for vaulted ceilings or a room-in-attic design, trusses can be created specific to your project and needs.
- Cost-Efficient: Labor costs are less than with rafters since trusses are made in a factory before they are transported to the job site for installation. In contrast, rafters are made onsite piece by piece, making rafters much more costly as well as time-consuming.
Difference Between Roof Trusses and Rafters
If a truss sounds a lot like a roof rafter, then you are correct to make that connection. The two have the same job of providing the roof framing and supporting the weight of the roof. However, one of the biggest differences between the two is that roof rafters are made with stick framing at the construction site.
A roof truss is designed by a computer and built to exact specifications in the factory, then transported to the site. They have become increasingly popular over the past 50 years because they are accurate, stable, and affordable.
FAQ About the Types of Roof Trusses
Technically yes. But it’s best to check with a structural engineer, as redesigning a roof could interfere with the structural integrity.
Typically, you need a truss every 2 feet. The best way to determine how many you will need is to measure the roof lengthwise along the slope, then divide by two, and round up to the nearest whole number.
There are three things to consider when figuring out what type of roof truss you have:
– Roof shape: For example, if you have a hip roof, you will have hip trusses.
– Ceiling type: For instance, if you have vaulted ceilings, it’s possible you have scissor trusses.
– Attic space: If you have an unfinished attic, you can look in that room to determine the type of truss used.
There are a lot of variables that will go into choosing a type of roof truss. At the end of the day, it’s best to consult a professional to ensure all your needs are met.
– Type of roofing material: Some HOAs can be very specific and particular, so check for any restrictions.
– Size of your home or addition: Depending on the size of the truss you need, this may help narrow down the type of truss.
– Project needs: If you want vaulted ceilings for your attic, a scissor truss is a great option. On the other hand, a raised heel truss is good for energy efficiency.
– Type of home: Whether it’s a ranch, Spanish, colonial, or farmhouse, you should choose a truss that will go with your home style.
Choose the Best Truss For Your Roof
Now that you have the knowledge of the different types of roof trusses, are you ready to pick the right truss for your home? If so, let us help you find a reliable roofing contractor who can do your project correctly and efficiently.
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