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We are the UK's largest and longest established manufacturer and supplier of engineered wood products, with eight branches across the UK and over 30 years of experience.

Largest Independent Timber Engineering Company In The UK

Open Web Joists

Open Web Joists

When spans are greater than 5m, open web joists - also known as Posi or metal web joists - become more cost effective. Open web joists also have the added benefit of easier installation of electrical, plumbing and ventilation services, and they are much better suited for future building modifications.

DTE's metal web joist system provides many benefits as well as offering best value to our customers. Located in the UK with eight regional branches, we are able to provide a complete national coverage along with local knowledge and service. We take you through the complete process including design, manufacture and delivery, together with providing any after-sales support that you may require.

imageOpen web joists (also known as Posi joists), are composite timber and steel joists forming an open web design. This provides the lightness of timber with the strength of a steel web. Our open web joists are lightweight, strong, easy to install and available in long lengths.

The open web design means that using these joists offers a flexible solution for any future internal building layout modifications, plus they eliminate costly cutting and drilling when installing services or incorporating modern ventilation and heat recycling systems.

DTE open web joists allow for longer clear spans or shallower depths than other engineered timber joists, and are ideal for floors or flat and mono-pitched roofs. They are also the perfect solution for environmental sustainability, as they can help cater for thicker insulation and mechanical heat recovery and ventilation systems, assisting with creating more energy-efficient buildings.

Open web joists are suitable for domestic, industrial and commercial applications.

DTE open web joists are individually engineered, lightweight, durable and dimensionally precise. They are supplied along with all associated metalwork and timber ancillary materials, including metal connectors, temporary bracing, chipboard decking and any additional timbers.

Advantages of open web Joists

  • Lightness of timber and the strength of steel
  • Easy handling and installation
  • Make installation of services easier, simpler and cheaper
  • Precision-manufactured almost eliminating need for site alterations
  • Long continuous spans
  • Reduce the need for intermediate support walls
  • Reduced site wastage
  • Reduced vibration and improved acoustic performance/li>
  • Long term stability
  • Environmentally sustainable

One Stop Shop

At DTE, we supply more than just trusses and joists. We can provide you with all the associated products you need for your roofing or flooring requirements, including:

  • Kerto LVL
  • Glulam
  • Spandrel panels
  • Roof or floor cassettes
  • Gable ladders
  • Metal connectors and straps
  • Stability bracing
  • Chipboard decking
  • Fascias
  • Barge boards
  • Soffits
  • Sheathing


If you have any further questions about our products, please get in touch.

DTE Posi Joist Brochure

Please download DTE’s Posi Joist brochure.

Download PDF

Recent Projects

Specialised roof packages for housing development

Work Included:Work Included: DTE worked with Barratt Homes on a large housing development in Surrey, providing a specialised full roof package for a block of flats and 110 houses.

Roof system for renovation of listed building

Work Included: The DTE Ilkeston team was required to supply a massive 20,000 roof trusses for 625 forest lodges within a rapid build programme.

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Head Office

Donaldson Timber Engineering Ltd
Muiredge Industrial Estate


01592 715026


01592 714007



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