More than 70 architects were among an audience of over 100 that attended the launch of the 2010 Directory of Specialist Leadwork Contractors. Organised by the Lead Contractors Association (LCA) and jointly sponsored by the Lead Sheet Association (LSA), the launch took place at the Institute of Materials, Minerals and Mining in Carlton House Terrace, London.

2009 saw the LCA celebrate their Silver Jubilee and Chairman David Martin opened the 2010 Directory launch by assessing the objectives he had set last year.

• More specifications nominating LCA members for the lead work
• Every leadwork project of historical, architectural or commercial significance to be carried out by a member of the LCA
• Contractors involved in leadwork that thought they knew how to design and install the material to prove it by applying to join the LCA and having their leadwork standards checked.

In looking back, Mr Martin considered that each objective had been addressed with varying degrees of success and he saw no reason why this momentum should not be continued as the LCA start their next 25 years.

He closed his presentation by posing the question to the architects and specifiers in the audience as to whether they had a responsibility to not only cover materials and standards of workmanship in their specifications, but also to ensure a registered competent contractor was used to install.

Joss Campbell, Chairman of the Lead Sheet Association welcomed the opportunity to put the case for lead sheet in modern day construction, emphasising the unique proven long term sustainability of the material that had now been in use in UK construction for centuries.

He emphasised the green credentials of lead, its total recyclability and, given its low melting point and comprehensive national materials reclamation network, the minimal carbon “footprint” of producing and using lead sheet.

Not least among the advantages of using lead sheet, he said, was the availability through the Lead Contractors Association of a quality controlled workforce to install the product, which maximised its long term performance credentials.

Mr Campbell went on to explain the complexities of the London Metal Exchange which set the price for lead but which was nevertheless at the mercy of market speculators who had no interest in the industry other than to trade in metal warrants the same as they did in stocks and shares on the London Stock Exchange.

Given the relatively small use of lead sheet in construction (some 200,000 tonnes world wide compared to 6M tonnes (and rising) in car batteries) the price of lead was therefore out of the hands of the UK sheet manufacturers and contractors. The recession and performance of the stock exchange had caused speculators to look for other markets in which to trade and the London Metal Exchange had proved an easy target, resulting in the spectacular price surges in recent years of the metals, including lead, that were traded on the LME.

The price surge in the LMA lead price in 2008 had led to the unwelcome escalation in thefts, particularly from vulnerable ecclesiastical properties. Thankfully, as a result of better site security, DNA type identification through using such as Smartwater and an improved accountability through the reclamation network, theft issues now appeared to be subsiding.

Mr Campbell said now the general expectation was for a period of metals price stability, as the financial stock markets were recovering and traders were returning to them for the more varied options than were available on the LME.

Carl Edwards, Managing Director of the CEL Group and Chairman of the LCA Promotions Committee then explained the differences between the three types of lead sheet available in the UK market, as there was often confusion among specifiers, or worse, a general assumption that they were all the same.

Rolled lead sheet was the most commonly used, produced from a refined cast slab on a computer controlled rolling mill that achieved thickness tolerances of +/- 5% at any point on the sheet, as required by the European manufacturing standard BSEN12588. Rolled lead sheet is bulk produced, generally in standard 3M and 6M roll lengths.

Traditional sand cast sheet is the oldest method of production (circa 16thC), where molten metal is poured onto a bed of sand, skimmed to the required thickness whilst still molten and then cut to size when cooled. Traditional sand cast is often specified as a like for like replacement in heritage work.

Machine cast, or Direct Method (DM) sheet is produced by immersing a rotating, water cooled drum into a bath of molten lead. The lead solidifies on the surface of the drum and is lifted from the bath and peeled away in sheets as the drum rotates. The thickness of the sheet is determined by the speed of the drum, the depth at which it is immersed and the temperature variation between the drum and the bath.

Machine cast lead was first introduced to the UK in the 1960’s in thin sheets as a sound attenuation material and not used in thicker sheets externally for roofing until the late 1970’s.

Machine cast is often assumed to be the same as traditional sand cast, Mr Edwards advised that architects should be clear in their specifications so as not to confuse the two completely separate types of metal.

Mr Edwards advised that the Lead Contractors Association 25 Year Guarantee Scheme can only be registered on a project where rolled sheet to BSEN12588 or traditional sand cast sheet is used.

Mr John Woods, Technical Officer from the Lead Sheet Association then proceeded to outline the technical support and assistance that is available for anyone using lead sheet or designing a project that involves the material.

Mr Woods showed details from the “Lead Sheet Manual” and emphasised the comprehensive nature of this superb reference guide that was offered in support of the services of the LSA Technical Office. LCA members could also help in advising the architect when it came to setting out a detail to be installed, to ensure that it complied with the current Code of Practice BS6915.

He showed many fine examples of workmanship and detailing, as well as a few examples where an uninformed specifier had not had the benefit of using an experienced and knowledgeable installer.

Mr Woods also provided details of the full range of training courses provided by the LSA at their new custom built facility in East Peckham, Kent.

The final presentation was by LCA Secretary Ray Robertson, which emphasised the significance of using a member of the LCA for leadwork

• An insurance backed and underwritten 25 year guarantee
• Work carried out to published standards (BS6915 current Code of practice)
• Regular inspections of installed work through an annual vetting programme
• Work is graded and grades published in the directory and web www.lca.gb.com
• Commitment to training for the future
• Design assistance for the architect and many provide a full design warranty

In summarising, Mr Robertson gave the easiest specification an architect could write:

“Lead sheet to BSEN12588 or traditional sand cast, to be fitted in accordance with BS6915 and the recommendations of the Lead Sheet Association (as defined and illustrated in the Lead Sheet Manual) and installed by a member of the Lead Contractors Association under their 25 Year Guarantee Scheme”

The event closed with the presentation of the 2009 Murdoch Award – the ultimate accolade for Excellence in Leadwork – to John Fulton (Plumbers) for their work at Elder Park Library in Glasgow. Created in 1996, the Murdoch Award is presented annually to a member of the LCA who, according to the judging panel, has produced the best example of the leadwork craft – effectively the very best of the very best in leadwork.

A commemorative framed photograph of the winning entry was presented by LCA Chairman David Martin to Associated Lead Mills, who have sponsored the Murdoch Award since 2004 and in 2006 introduced the Murdoch Sponsors Award for leadwork projects under 5 tonnes.

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For technical or training information contact the LSA on 01622 872432