In the world of construction, innovative solutions are constantly sought after to improve efficiency, sustainability, and cost-effectiveness. Metal web joists, also known as open web joists or Posi-joists, emerged as a game-changer in the industry. The advantages of metal web joists surpass those of traditional solid timber joists, making them a popular choice among industry professionals and housebuilders.

What are Metal Web Joists?

  • Metal web joists consist of a network of lightweight steel webs sandwiched between timber chords.
  • This unique design combines the strength and stability of steel with the versatility and workability of timber.
  • The metal webs are precision-engineered, ensuring accurate and consistent dimensions, resulting in a reliable and high-quality product.

Strength and Load-Bearing Capacity:

  • Metal web joists have exceptional strength and load-bearing capacity, surpassing that of traditional timber joists.
  • The steel webs provide rigidity and stability. This allows these joists to span greater distances, enabling larger room sizes and greater design flexibility.
  • The increased load-bearing capacity makes metal web joists suitable for various applications, including residential, commercial, and industrial buildings.

Clear Openings for Services:

  • Metal web joists feature an open web design. These create clear and uninterrupted spaces for the installation of building services such as plumbing, electrical, and HVAC systems.
  • This eliminates the need for complex and costly modifications to the joist structure, reducing construction time and improving overall efficiency.
  • The clear service openings simplify the installation process and allow for easy maintenance and access to services in the future.

Thermal Performance:

  • Metal web joists excel in providing excellent thermal performance, addressing the need for energy efficiency and sustainability in construction.
  • The design allows for the installation of insulation between the steel webs, ensuring a consistent and continuous layer of insulation across the floor structure.
  • This helps to reduce heat loss, improve energy efficiency, and create a comfortable living or working environment, while also contributing to higher energy efficiency standards and building regulation compliance.

Fire Safety:

  • Metal web joists are designed with fire safety in mind, making them a reliable choice for construction projects.
  • The steel webs act as fire-resistant barriers, impeding the rapid spread of fire and providing additional time for evacuation and firefighting efforts.
  • These joists can be engineered to meet specific fire safety requirements. They are suitable for various applications, including multi-story buildings and fire-rated floor assemblies.

Speed and Ease of Installation:

  • Metal web joists offer significant time and labour savings during installation due to their lightweight construction.
  • Their ease of handling and manoeuvrability on-site reduces the need for heavy lifting equipment, improving overall efficiency.
  • The open web design facilitates the threading of services, simplifying the installation process and ensuring quick and accurate assembly.

Design Versatility:

  • Metal web joists provide unparalleled design versatility, allowing architects and engineers to create innovative and customised building structures.
  • Their ability to span greater distances without intermediate load-bearing walls opens up endless possibilities for architectural design.
  • This versatility extends to both residential and commercial applications, enabling the creation of open-plan living spaces, mezzanine floors, and unique architectural features.
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Sustainability and Environmental Benefits:

  • Metal web joists offer notable environmental benefits, aligning with the growing emphasis on sustainability in construction.
  • The use of engineered wood components and lightweight steel webs minimises material waste and optimises the use of timber resources.
  • Additionally, the thermal performance of metal web joists contributes to energy efficiency, supporting green building practices and reducing the environmental impact of construction projects.


Due to the advantages of metal web joists, they have become the preferred choice for industry professionals and housebuilders over traditional timber joists. By utilising these innovative joists, construction projects can achieve greater efficiency, cost-effectiveness, and environmental sustainability.

The strength, load-bearing capacity, clear service openings, thermal performance, fire safety features, ease of installation, design versatility, and sustainability benefits make metal web joists an excellent solution for creating exceptional buildings that meet the demands of the modern world.

About Nuneaton Roof Truss

As the UK’s largest independent manufacturer and supplier of prefabricated roof trusses, Attic Trusses, Spandrel Panels and floor joists, Nuneaton Roof Truss is the manufacturer of choice for all engineered timber requirements.

Click the link to get a quote or call us on 02476 327722 to find out how we can support your business and projects.

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