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Building News: New BAZ screw gets thumbs up from RIDBA

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EJOT ® The quality connection

New fastener solves slippage problem for the Big Six Profile roofing sheet

Story added October 2015

When RIDBA raised concerns relating to slippage of traditional agricultural profiled sheets, EJOT UK took the call for action seriously and has now launched the first BAZ Screw developed specifically for the Big Six fibre cement roofing profile.

RIDBA’s concerns were that once in position, roofing sheets are subject to natural movement created by the environment and the passage of time - which may cause the hole between fixing and purlin to enlarge, putting a strain on the securing washer. Tests carried out at the time seemed to endorse the theory across a range of commonplace industry-supplied fastenings.

Another consideration was that the top fix self-drilling fastener for fibre cement sheeting was originally developed when steel supports were between 1.5mm and 6.0mm in thickness - designed for traditional hook bolts. As yield strengths of modern steel purlins have increased thicknesses have decreased, and it is common to see purlins of 1.3mm,1.4mm in some instances as low as 1.2mm being used!

Kevin Rackley, product manager for EJOT UK picks up the Story:
“We had a case of a common application with a problem and in need of a solution. Fastener design and development is what EJOT is all about and our R&D team were quick to run with this industry-wide challenge”.


Modifications and tests were scheduled in for EJOT’s traditional wing-drilling fastener, with the aim of becoming the first manufacturer to create a bespoke solution rather than provide a ‘fits-all’ offering. Re-engineering focused on eliminating any possibility of the panel ‘jacking’ and to look at the installation holistically during installation. All installers will be aware that potentially, this will lead to an oversized hole. EJOT’s Applitec development team achieved its objective by precise repositioning of the fastener’s ‘wings’ whilst shortening its length. The drill point and thread configuration was analysed leading to the development of a purpose designed fastener to accommodate and provide positive engagement into purlins of 1.2mm to 2mm thickness. Even the length of the fastener has been designed to ensure that the BAZ washer sits against the sheet sooner, to avoid any movement that could unduly elongate the installation hole in thinner purlins.

Pull-out tests carried out at Applitec in September show the fastener recording an ultimate mean performance of 3.8 KN from 1.4mm steel purlins and an impressive 3.0 KN from 1.2mm galvanised steel purlin sections, clarifying that the fastener not only improved on the installation performance but also from a technical standpoint.

Antony Lowther of frame manufacturer AJ Lowther and Son Ltd witnessed the original tests that questioned the broad range of fixings being supplied to fix the Big Six profile. He has been amongst the first to trial EJOT’s new fastener:
“This new fixing is absolutely solid. Two years ago we were shocked to find that some fixings could be wound back out of the purlin with fingers; there is no way this fixing is going to back out.”

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Download the BAZ JT2-FZ-3-6.3 x 90 flyer here or contact EJOT customer service on 01977 687040 during office hours.

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EJOT® - The Quality Connection - This statement captures the Group's ethos. On one hand, it reflects the uncompromising efforts made to achieve the highest possible levels of product quality. On the other hand, it underlines that, technical standards aside, the human aspect both inside and outside the company are just as important. Just one reason they call EJOT® the quality connection.