Metal Web Joists Questions and Answers
What are Metal Web Joists?
Metal Web Joists consist of parallel stress timber flanges joined together with engineered V-shaped galvanised steel webs. The webs are fixed to the flanges via nailplated zones top and bottom.
What's the difference between Metal Web Joists, Ecojoists and SpaceJoists™?
What’s in a name? There is no difference, just a different name for the same high quality product.
How far can Metal Web Joists span?
This will depend on the loads, overall depth and width of the joist. Our teams can advise.
What is the strongback bridging for?
This is to create a “solid” feel to the floor structure by ensuring good load sharing between joists, thus limiting the effects of vibration.
What about fire?
Like all timber based floor systems Metal Web Joists relies on the plasterboard fixed to its underside for the majority of its fire resistance. Generally speaking, 15mm plasterboard with a skim coat of plaster or artex will provide the modified 30-minute fire resistance required for domestic first floors.
Why is there an opening in the middle of the beam?
The positions of the webs are calculated from the end (or support point) of the joist towards the centre with any discrepancy being taken up in the middle bay.
Can I deck the floor at joisting stage, to provide a safe working platform?
Yes, Metal Web Joists lend themselves ideally for this application, being open web constructed, services can be installed retrospectively, through the open space. (A 195mm deep beam will accommodate a 100mm plastic pipe). We recommend the use of Proprietary Weatherproofed Flooring – which can be laid at the joisting time and offers the opportunity to build a safe working platform as well as the finished floor in one operation.
Can I use Metal Web Joists in floors to meet 'Part E' for flats?
Yes Metal Web Joists outperform most joist systems and when a 253mm deep joist combined with a 36mm Eleco floor panel laid as a floating floor over standard decking, together with 15mm plasterboard below, have test results of 57db and 58db respectively for airborne and impact sound insulation. This applies to timber frame construction only.
Can I use Metal Web Joists to meet building Regulation Requirement E2 for dwelling houses?
Yes, tests prove that 219mm deep Metal Web Joists at 600mm centres when used with 22mm Chipboard decking screwed or nailed to joists together with 15mm Wallboard plasterboard fixed to the underside, offer a sound reduction of 40dB (Rw=40dB).