The preservative treated JJI-Joist is the only UK manufactured I-Joist which is low pressure treated for use in projects that require protection to UC1 and UC2, in compliance with BS EN 331-5.

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.”

James Jones Timber Systems