Zinc roofing and cladding, getting the build-up right

Over the last 30 years the number of aesthetic options for zinc roofing and cladding have multiplied. Pre-weathered light grey QUARTZ-ZINC and dark grey ANTHRA-ZINC have now been joined by seven standard PIGMENTO finishes which add subtle colour whilst keeping the texture of zinc. Engraved AZENGAR gives a brightness to zinc while retaining its matt aspect.

Traditionally, most zinc wall panels such as standing seam and flat lock are installed over continuous substrates. With the increased use of rainscreen systems, Mozaik panels which can be up to 600mm wide to more linear Interlocking panels which can be installed both horizontally and vertically, are fitted to Aluminium cladding rails.

These systems and finishes can all be used on both retrofit and new build and from small to large scale projects, however it is always important to use the appropriate substructure.

For the first 180 years of zinc roofing cold, vented construction was the order of the day but for almost 30 years VMZINC have offered non vented warm roof build ups. For all warm roof construction moisture from the inside of the building in the form of vapour must not be permitted to enter the insulation. For the BBA certified Structural roof this means that the Aludex Max vapour barrier must be fitted over a continuous support with the insulation above. Not only does the system have far improved air tightness but thermal bridges are greatly reduced. It should be noted that both vented and non-vented roofs are covered by BS 476-3 and CEN/TS 1187 Brooft4 for no flame penetration or spread.

For fully supported standing seam wall cladding a traditional timber substrate can be replaced with a metal deck and by using a stone wool insulation the main elements of the facade are non or of limited combustibility following EN13501, A1 and A2. All vented cavities must be suitably fire stopped.

A correctly designed zinc roof or façade will perform with almost no maintenance for many decades. The BRE EN15804 Environmental Product Declaration references a service life of 100 years. It is also important that the roof or façade be installed correctly and since 2014 VMZINC has been operating the VMZINC@WORK partner program. The program supplies added training to already skilled hard metal contractors thus further driving up quality and workmanship.

If you would like any further information including samples or an online RIBA accredited CPD please do not hesitate to contact us: www.vmzinc.co.uk