These joists are also FSC or PEFC certified, and their strength properties are independently assessed by TRADA.
The deeper, slimmer JJIs are available up to 450mm and are a response to the increasing specification of JJI-Joists for roofs and walls where a high level of thermal performance is required.
James Jones Timber System’s Business Development Manager Mark Tilston commented:
“These new products offer architects and other specifiers a wider range of choice. Our preservative treated JJIs provide a cost effective and quality assured solution for advanced timber frame systems; and the deeper, slimmer JJIs are ideal for carrying additional insulation for high performance roof and wall systems.”