A perpendicular lined indentation that can appear throughout the entire length of a lead roll at spacing equal to that of the circumference of the roll - the distance between the lined indents decreasing the closer you get to the roll centre.
Despite the feedback from Contractors, this matter has mostly been ignored by the industry and their supporting associations.
Some manufacturers do claim to run special Barmark free mills – in essence, admitting to the problem. Yet even these are reportedly* no better quality than product that is produced on regular mills.
*Feedback received by us from highly respected industry artisans.
Will a Barmark affect the performance of the Lead sheet?
It is unlikely that a Barmark will affect the performance of the lead sheet. However, aesthetically (in particular, when laid in bays) the Barmark can be an unsightly and unwanted addition to the overall aesthetic of your finished lead roof. Some Barmarks being so prominent that they are easily viewable from ground level.
How can you remove a Barmark?
"With difficulty", is the only real answer! Traditionally, on lighter codes, the Barmark would have been ‘flapped’ out (using one sheet strip of lead and physically flapping it repeatedly on the Barmark until it disappeared). On the heavier codes, the only option being to heat the lead and dress it out. Both of these solutions are painstakingly slow and are completely unacceptable today.
So what’s the answer?
As the industry continues to shrug its shoulders at this problem, Abbey Metals has hit the issue head on.
Abbey Metals now cuts its lead flat and not from bobbins, resulting in the finished product being cold coiled and therefore less likely to suffer from any kind of indentation caused from mandrel key or backstop marks.
Message to Specifiers and Contractors
For a long time, the Barmark has been a bane in the leadworks life.
Artisans complaining that the quality of their work has been undermined by the inability of Lead Manufacturers to fix this age-old problem.
Clearly, not all Rolled Lead is the same..!
To protect your reputation ALLWAYS ensure that you specify that your lead has:
BSEN Certification , 50 year warranty and is BARMARK FREE.
Contact Abbey Metals for the name of your local stockists.