10 Common Types of Roof Trusses and Their Applications

Roof trusses are essential structural frameworks supporting roofs in residential, commercial, and industrial buildings. Choosing the right roof truss type ensures structural integrity, cost-effectiveness, and aesthetic appeal. This article explores 10 common types of roof trusses used across the United States, highlighting their design characteristics and typical applications to help builders, architects, and homeowners make informed decisions.

Truss Type	Design Features	Common Use
King Post Truss	Simple triangular shape with central vertical post	Small-span residential roofs
Queen Post Truss	Two vertical posts with a horizontal tie beam	Moderate spans in homes and small buildings
Fink Truss	W-shaped web for efficient load distribution	Most common for residential roofs
Howe Truss	Verticals in tension, diagonals in compression	Large industrial and commercial roofs
Pratt Truss	Diagonal braces in tension, verticals in compression	Bridges and long-span roofs
Scissor Truss	Intersecting bottom chords form vaulted ceiling	Cathedral ceilings in homes and churches
Attic Truss	Built-in attic space within truss structure	Homes requiring extra storage or living space
Mono Truss	Single sloping beam, simple design	Lean-tos, additions, and sheds
Mansard Truss	Double-pitched slopes on all sides	Victorian-style homes with extra living space
Flat Truss	Horizontal top and bottom chords	Commercial buildings with flat roofs

King Post Roof Truss

The King Post truss is the simplest and one of the oldest truss types, featuring a triangular shape with a central vertical post. This design efficiently transfers the roof’s load to the bearing walls, making it ideal for smaller spans under 30 feet. It’s commonly used in residential buildings and sheds due to its straightforward construction and cost-effectiveness. However, its limited span restricts use in larger structures.

Queen Post Roof Truss

Extending on the King Post design, the Queen Post truss uses two vertical posts connected by a horizontal tie beam. This arrangement supports moderate spans between 30 and 60 feet. It provides greater open space beneath the roof compared to the King Post and is suitable for medium-sized homes and small commercial buildings. Its balanced load distribution offers durability and stability.

Fink Roof Truss

Widely recognized as the most common roof truss type in American residential construction, the Fink truss utilizes a distinctive W-shaped web formation. This design offers excellent load distribution with economical use of materials. Suitable for spans from 30 to 60 feet, the Fink truss supports steep-pitched roofs typically used in suburban homes, delivering strength and efficiency.

Howe Roof Truss

The Howe truss features vertical members in tension and diagonal members in compression, differing from other truss designs. Ideal for longer spans ranging from 60 to 100 feet, it’s frequently employed in large industrial or commercial roofs and bridges. Its robust load-bearing capacity allows it to handle heavy roofing materials efficiently.

Pratt Roof Truss

Characterized by diagonal members under tension and vertical members under compression, the Pratt truss offers strong resistance to bending forces. It is commonly found in bridge structures but is also used in wide-span roofs, such as warehouses and gymnasiums. Its design is favorable for handling dynamic loads and wind pressure.

Scissor Roof Truss

The Scissor truss is notable for its intersecting bottom chords that create a vaulted ceiling effect below the roof. This design allows for high, open interior spaces, making it popular in residential homes, churches, and auditoriums. It efficiently distributes structural loads while offering an elegant architectural ceiling profile.

Attic Roof Truss

Incorporating additional internal space, the Attic truss provides a built-in attic area within the truss framework. This design maximizes usable space for storage or living purposes without increasing the building’s footprint. It’s ideal for residential construction where extra rooms or storage are needed on upper floors.

Mono Roof Truss

The Mono truss has a single sloping top chord and is often used for smaller roof sections such as lean-tos, porches, or house additions. Its simplistic design facilitates fast installation and is cost-effective for short spans typically under 20 feet. The Mono truss is versatile and commonly used in residential upgrades.

Mansard Roof Truss

The Mansard truss supports a distinctive four-sided roof with two slopes on each side, the lower slope being steeper. This creates a spacious attic or living area suitable for Victorian or French-style architecture. Though more complex and costly to build, it enhances aesthetic value and usable space.

Flat Roof Truss

Flat trusses feature horizontal top and bottom chords, supporting roofs with little to no pitch. These trusses are extensively used in commercial buildings, warehouses, and modern residential designs where a flat roof is desired. They allow for easy installation of HVAC systems and rooftop equipment.

Summary

Selection of the appropriate roof truss type depends on factors such as building size, roof design, and intended use. Understanding the characteristics of each truss helps optimize structural performance and cost. From small residential King Post trusses to large-scale Howe and Pratt trusses for commercial applications, these 10 types cover a broad spectrum of building needs.