When it comes to I-Joists, first choice amongst builders and architects is the James Jones’ JJI-Joist, the UK market leader, with an estimated 40% market share. I-Joists are now used in the vast majority of houses built today.
However, JJI-Joists are used for much more than floor systems. JJI-Joists are now commonly used as wall studs where the range of depths and 9mm web make them ideal when thermal efficiency and depth of insulation are paramount. And JJI-Joists are also increasingly used in roof structures as well, either as rafters or where cassette panels, formed using JJI-Joists and OSB or plywood sheets, are used to create a fully insulated ‘room in a roof’. The 12m span achievable with a JJI roof cassette makes them a popular choice for large span requirements such as schools, health centres and other public buildings.