Floor Joists

Open Metal Web Joists

Our choice of floor joist

When choosing a floor joist system or a flat roof system, the range of options on the market can be confusing. They all have their own advantages.

Merronbrook has specialised in timber construction for thirty years and in that time, we have found that open metal web floor joist systems offer the best value to suit our customers’ requirements.

The increasing presence of services running throughout the modern dwelling means having the ability to run services easily through the floor zone is imperative. Traditionally, the floor zone would be cut, notched and drilled to accommodate these services. This not only increases works on site but could severely compromise the performance of the joist system.

Metal Web Floor Joists – The Smart Choice

Open metal web joist systems have become the smart choice for developers, due to the many benefits they offer from longer spans to greater service-carrying capacity and design flexibility. Merronbrook uses the easi-joist® system from Wolf®, chosen for its innovative design options, years of engineering excellence and integration with our existing products. Specifying easi-joist® eliminates the requirement of drilling or notching with its ability and outstanding flexibility to accommodate the design-on-site approach of any modern home, commercial or industrial buildings.

For more information, please see our FAQs page.

What Is Easi-joist?

Easi joists are parallel chord trusses using stress-graded timber chords, plated together with Wolf Systems patented, precision-engineered webs.

Profiles, end widths and depths, based on single joists.

Merronbrook’s offering of the easi-joist® is available in 4 depths from 219mm to 417mm, utilising 47mm top and bottom timber chords. The widths vary from 72mm to 147mm and can also be constructed as double joists, if required. Fixing multi-ply joists is to be carried out to metalwork suppliers’ instructions using propriety fastening screws. Depth, width, and centres will all be determined by easi-joist® software.

Easi-joist® is designed to allow for easy accommodation of electrical, plumbing, wastewater and other services required within the floor joist area with no cutting or nothing required.

The Easi-joist®, Depths and Widths Range

Click on our interactive Floor Detailing Key to find out more.

Floor Detailing Key

Home Easi-joist® Masonry Hangers with Perimeter Noggins Detail Easi-joist® Strongback Size and Installation Easi-joist® Built into Block Wall Detail Easi-joist® Joist to Joist Hanger Detail Easi-joist® Horizontal Restraint Strap Detail Easi-joist® Joist to Panel and Rim Board Detail Easi-joist® Joist to Joist ‘Top-Chord Support’ Detail ICON 3 - Eaves Eaves Detail Back ICON 2 - Floor Edge Floor Edge Detail Back ICON 1 - Sole Plate Back Soleplate Detail

Easi-Joist® Open Metal Web System

We use Wolf Systems’ industry-leading easi-joist® open metal web system. Combining the benefits of sustainable, kiln-dried, stress-graded timber with the rigidity and strength of the easi-joist® metal web construction, we provide lightweight floor beams, engineered to precise dimensions.

The advantages of our floor joist system include:


When installing services in a traditional engineered I-joist, holes need to be cut into the supporting web – a practice which takes time and, in some cases, can affect the structural integrity of the joist. As its name suggests, the easi-joist® open metal web system allows easy installation of services such as pipes, cabling, trunking and ducts in the floor zone. Among its advantages, using this system reduces build time, saves on labour costs and limits any possibility of incorrect workmanship.


I-joists and other comparable systems can experience levels of moisture and shrinkage that ultimately affect the structure’s long-term stability. The combination of our stress-graded timber and the open metal web system greatly reduces shrinkage factors and results in a quieter and longer-lasting floor system.


The sturdy construction of metal web floor joists allows for a much longer span, in comparison to other types of joist.


Aside from being strong and robust, the easi-joist® system is a lightweight floor joist solution as it combines smaller timber sections with a lightweight metal web.


Easi-joist® metal web floor systems allow for the installation of a rigid Strongback that reduces vibration and improves the overall acoustic performance of the floor.


The precision-manufactured easi-joists® and floor cassettes all reduce the installation time of the metal web floor system in comparison to traditional techniques, by excluding the need for further drilling and cutting on-site.

Merronbrook’s USPs for the easi-joist® system

Weather Decking

Merronbrook offers 2 different weather decking systems:

  • Egger Protect
    Painted surface only
  • Krono Fast Protect
    This one has a peel clean surface, once peeled a painted surface is left

Both boards are the same size (2400 x 600 x 22mm)

D4 Glue

In accordance with the manufacturer’s (decking) guidance, D4 should be used.

Returnable Boxes and Labelling

Merronbrook offers a unique Returnable Box Scheme for our truss & joist metalwork. This enables clients to be reassured that the connectors for their project have been picked, checked, labelled and security-packaged before despatch to site, ensuring that the right connectors are used on the right plots, fewer errors and less time lost, due to hunting for missing connector packs. Our unique product labelling and site instructions are tailored to our easi-joists®  on every box.

Masonry Hanger Options

Merronbrook uses ITW / Cullen metalwork.

  • Option 1use a standard masonry hanger called JHI
    Advantage is low cost. Disadvantage requires a minimum of 3 block courses (675mm) fully cured before the floor can be loaded.
  • Option 2use masonry hanger called RBJHI (RB = Rapid Build)
    This more robust hanger offers you several advantages compared to the standard JHI, this hanger does not require masonry above providing a safe working platform. Hanger offers no restraint and parallel straps are required.

How does Merronbrook manufacture their easi-joists?

Read more about Floor Joists

Flat & Pitched Roof Joists

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Easi-joist Span Calculator

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