21 Main Types of Trusses for Houses |Wood/Timber Trusses Pros & Cons | Steel Trusses Pros & Cons
Types of Trusses for Houses |Wood/Timber Trusses Pros & Cons | Steel Trusses Pros & Cons
What are Trusses?
Trusses are the structural frames that are used to support the roof of a building. Most trusses are triangular in shape and are able to span large distances. Trusses are the most popular type of frame construction that mostly used for residential homes.
Houses built with trusses end up lighter and with less lumber, which in turn makes them easier to construct overall. Truss types can vary depending on the region but typically they are three-dimensional trusses.
Span of a Truss
The span of a truss is the length of the lowest chord that spans the breadth of the room or structure covered by the truss. The span should not be mistaken with the truss’s entire width, which includes the overhangs.
1. Wood/Timber Trusses
Wood trusses are the most common type of truss used in buildings today. They consist of wood boards that have been cut to fit together (laminated) and connected with wood or metal pins.
These under-pinned members can be used beneath roofs for homes or, more commonly, above ceilings to form a framework for a building’s roof.
Wood trusses are similar to a skeletal structure, where the joints between the elements allows the truss to “breathe” and expand and contract without causing damage.
Wood trusses can be made from wood, composites, or other materials. The structure is usually divided into three sections: top, middle, and bottom.
Types of Wood Trusses
There are three types of wood trusses: parallel chord, compound and tri-angles. Each type has its own particular advantages and disadvantages.
1. Parallel chord.
Parallel chord trusses are a type of wood seen in low-pitched roofs. This type of truss consists two parallel chords that run from one side to the other, creating a “v” shape. The chords are then connected together by using beams and pins.
his method is primarily used when the vaulted ceilings are extremely high. In practice, cathedral ceilings are more commonly associated with parallel chord wood truss roofs. The truss, as the name implies, runs parallel with very minimal arch.
2. Compound trusses
Compound trusses are also constructed from two parallel chords. However, they differ from parallel chord trusses because of their additional support member in the middle of the structure.
The middle member is used to carry weight from one side to the other and to add additional support for joint connection between top, middle and bottom chords.
3. Tri-Angles Truss
The tri-angles truss consists of three members, connected together at a joint in the center, top and bottom chords.
This type of truss is more expensive when compared to other types because it can span greater distances and have higher loads.
4. Scissor roof.
This is another popular option for high-ceilinged structures. It’s essentially a cross between a cathedral ceiling and a traditional flat attic. As a result, there is more headroom now that the rafters have been removed.
5. Dropped chord.
The dropped chord roof, like a raised heel wood truss roof, is good for insulation. It’s basically a standard truss with a second one suspended about a foot below to eliminate uplift.
6. Raised heel.
This Raised heel design is ideal for increasing energy efficiency in households and businesses. With this design, the raised section will extend to the outer wall’s meeting point, creating an extra area to use as you see fit.
According to research, a raised heel roof might save you between 4-6 percent on your energy bills.
Advantages of Wood/Timber Trusses
· Wood/Timber Trusses are cheaper than solid beam construction.
· Wood/Timber Trusses can span larger distances that other types of construction.
· Wood/Timber Trusses can be built by unskilled labor which is cost effective for residential use.
· Wood/Timber Trusses can be quickly erected.
· Wood/Timber Trusses are not detrimental to the environment because of the renewable resources used in their production.
Disadvantages of Wood/Timber Trusses
· Wood/Timber Trusses are less efficient in span when compared to steel or concrete beams.
· Wood/Timber Trusses easily rot and can even be eaten by insects.
· Wood/Timber Trusses do not provide any insulation, air pressure, or insulation on the sides of the structure when compared to rigid frames.
· Wood/Timber Trusses are more susceptible to damage from high winds because of their open-bottom shape.
2. Steel Trusses
Steel trusses differ from wood trusses by offering a stiffer system that resists changes in temperature and light.
Steel trusses are also less likely to damage with time, which is why these trusses are such a popular option for construction projects.
Steel is also preferable to wood because it’s heavier, which gives steel and increased resistance.
Advantages of Steel Trusses
· Steel Trusses offer a long-lasting alternative to other truss types because of its increased durability.
· Steel Trusses are relatively less expensive than other types of trusses.
· Steel Trusses are strong enough to handle large loads and spans.
· Steel Trusses is an excellent insulation material because it can provide protection against the elements as well as sound from going in and out of the house through the roof structure.
· Steel Trusses are fireproof, which means that they can protect a building’s structure from the effects of fire.
Disadvantages of Steel Trusses
· The process of creating a steel truss structure involves the use of environmentally damaging processes, such as smelting and casting, and can be harmful to the environment.
· Steel trusses are heavier than wood trusses; therefore, they are harder to transport and to erect.
· Steel Trusses are a costly option for homes when compared to wood trusses because of the difficulty in its production.
Types of Steel Trusses
There are several different types steel trusses used for residential construction. Each type differs in its size, shape, and layout of the truss’s members.
1. Sloping Trusses
Sloping Trusses are a type of steel truss that are used for residential structures with roof pitches ranging from 3/12 to 8/12.
Sloping trusses are usually only seen in residential projects where the roof pitch does not exceed the maximum 11/12.
The truss’s members start from a vertical position and slope upward or downward until they connect with another member at the top or bottom of the beam or member.
2. Box Trusses
Box Trusses are also used in residential projects. However, the box truss differs because of its shape and layout of the members.
There are two types of members, horizontal diagonal and vertical diagonal. These types of members connect horizontal, vertical and diagonal beams together to form a box-shaped structure that is often curved or zig-zag shaped.
3. K-type Trusses
K-type Trusses are used in residential projects as well. The K-type truss is similar to the box truss because of its members and construction components.
However, the K-type truss differs because it has a horizontal beam that runs across the top chords instead of vertical beams at the top and bottom.
3. Composite Trusses (or Wood Truss)
Composite Trusses contain layers of various materials such as wood, stone, metal or plastic. The trusses are also used for roofing, partition and ceiling construction.
They are very much advantageous as they can replace wood or steel structures at low cost.
Advantages of Composite Trusses
· They are cost-effective, able to be produced in small quantities and can be easily assembled.
· They are lightweight and so can easily be transported.
· They can withstand high-impact loading and fire damage.
· They are earthquake resistant, able to perform very well during earthquakes because of their flexibility in the structure’s members and beams.
· They are a perfect alternative to other wood or metal trusses because they are environmentally friendly, emit no toxic gases and do not use harmful chemicals.
In conclusion, Trusses both have their advantages and disadvantages. It will be up to you to decide which is the best option for your home.
In choosing what truss to put on your structure is important to consider what type of materials you want (wood or metal) and how much money you want to spend on the structure.
Types Of Trusses for Houses
Because of the additional complication in framing the hips, hip trusses are more complex to frame than other trusses.
A Half-Hip Truss has the same structure as a Hip Truss but is split in half.
The most frequent type of truss utilized in residential constructions is Fink Trusses. These trusses support the rafters and offer rigidity to the roof.
These trusses support the rafters and offer rigidity to the roof.
A cambered truss is a truss with a curved upper chord. The curve can be either a circular shape or a shape that is less circular, but more like a bow tie.
Cambered Trusses arch upwards, giving the roof a peaked shape while giving the ceiling the appearance of being curved.
A double-W truss, also known as a double-fink truss, may span more than 65 percent longer length (16.5m) than a single(10m) fink truss.
Because of its exceptional structural strength over extended spans, the Howe Truss was originally developed for steel bridges. It is uncommon in residential construction.
The Double-Howe Truss can span nearly twice as far as the single Howe, allowing it to reach up to 18m.
Even though scissor trusses do not require a bearing beam, they have a higher load limit than many other types of trusses. Furthermore, this style of truss improves the building’s stability.
Furthermore, this style of truss improves the building’s stability.
The Half-Scissor Truss is half the size of a standard scissor truss and is used in commercial, industrial, and residential environments.
The King-Post Truss is the most common form of truss. It has two rafters, a tie beam, and one center post called the King Post. The King Post Truss is frequently combined with two angled struts.
A Double-Inverted Truss is made up of two inverted trusses that unite at the summit and can span distances of up to 24m.
A Stub-End Truss, also known as a Bob-Tail, is a gable-shaped truss with one end trimmed. Each side’s slope has the same pitch but an uneven apex.
Flat trusses have a very little slant to prevent water from accumulating.
The Inverted Truss is a Howe Truss that has been turned upside down. This style can provide additional natural light to the interior space as well as a vaulted ceiling in a portion of the space.
Gambrel trusses are symmetrical and have a double slope, giving the roof a barn-like appearance. The gambrel truss is very useful since it maximizes the amount of usable space in the attic.
The Mono-Pitch Truss design is half of a standard truss design and is commonly used for buildings such as sheds and lean-tos.
Bowstring Trusses were originally utilized in bridge design because they function well in broad open expanses with no supporting columns. Because the pattern is arched, there is no seam to conceal.
The Barrel-Vault Truss achieves an arched ceiling by using several little pieces of wood in the frame.
Dual-Pitch Trusses are used for gable roofs with steeper slopes on either side of the peak. The front slope is usually steeper than the back.
Attic trusses are meant to create a place for additional storage or living space while maintaining the shelter’s outer look.
A Piggy-Back Truss is a combination truss that uses a gable end truss atop a hip truss so that the two can be moved or built-in pieces when a single triangular truss is too large.
Multi-Piece Trusses are trusses that combine a gable design on top of a hip design to allow them to be built in portions that would otherwise be too huge.
Sloping Flat Trusses
Sloping Flat Trusses, like Inverted Trusses, are used to create vaulted ceilings.