They offer several advantages over traditional structural timber products including long lengths, a composition that resists shrinking and warping, an excellent strength to weight ratio, straight and uniform dimensions and, uniquely, are FSC® and PAS 2050 accredited.
The JJI-Joists have the largest standard range available in the UK and are available in depths from 195mm up to 450mm deep with four flange sizes to facilitate a high degree of design optimisation putting the right product in the right place. The four flange widths are illustrated below along with a table showing the full range of JJI-Joists available.
You can see how JJI-Joists are made here:
JJI-Joists are only sold through a network of UK distributors, please see the map below to find your nearest distributor.
Find a JJI-Joist distributor
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JJI-Joists are available in a range of sizes familiar to the UK construction industry with joist depths ranging from 195mm to 450mm and with ﬂanges ranging from 47mm to 97mm in width. Dependent on joist depth, JJI-Joists are available in 8, 9, 10 & 12m lengths.
Flame retardant (FR) treatment
James Jones and Sons have been heavily involved in the Structural Timber Association Limited's (formerly UKTFA) on-going project to develop fire design guidance and test methods aimed at mitigating the risk of fire during construction of timber frame buildings.
As part of this work we have performed fire tests with flame retardants from two manufacturers with positive results. Where there is no alternative it is possible for us to supply a non-standard FR treated joist that complies with the Structural Timber Association Limited FR build requirements.
Pricing and delivery times on application.
JJI-Joists are untreated and when used in a Service Class 1 or 2 environment, the ETA certificate advises that they may be taken to have a service life in excess of 50 years.
JJI-Joists are available with preservative treated timber flanges. This allows their use in Use Class 2 conditions in accordance with BS EN335-1, and Hazard Class 2 conditions in accordance with NHBC
Standards, i.e. load bearing external wall studs and flat roof joists. This treatment does not affect the structural properties of the JJI-Joist. Please contact James Jones and Sons for further information.
JJI-Joists are available from a network of authorised distributors, timber frame manufacturers and other stockists located strategically throughout the UK and Ireland.
Our authorised distributors offer an estimating and design service inclusive of JJI-Joist layout plans, engineering calculations and material costings.
Click on the map to find your nearest JJI distributor
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