Architects are increasingly turning to zinc as a building material, for its long-term performance, low maintenance qualities and adaptability to diverse design styles. In the U.K., its use as a guttering material has been overshadowed by more widespread awareness of rainscreen cladding and roofing projects, but with increasing demand for metal guttering systems, both in residential and commercial developments, the combination of zinc’s strength, UV resistance, light weight, appearance and sustainability all combine in its favour.
In Western Europe, zinc guttering is part of everyday building practice. In France, this dates as far back as the 1860’s redevelopment of Paris in which Baron Haussmann used zinc extensively. It is now a common sight there on buildings of all ages, as the grey patinated appearance complements brick, stone, cladding and the plethora of glazing finishes used in modern commercial structures. Such flexibility and its contemporary appearance give it a design edge against more traditional profiles. Pre-weathered and even coloured finishes are now available, obviating any objection to the need for natural ageing.
The pre-weathered patination continues to mellow slowly over time, but the original appearance is retained without fading. Unlike aluminium, there is no generally need to paint or protect it as finishes such as VM Zinc’s Quartz-Zinc and Anthra-Zinc are the result of the modification of the metal’s crystalline structure rather than a surface coating. They have a typical design life of 50 years or more and are ideal for properties for which long-term maintenance costs are a major consideration.
Zinc has none of the attendant drawbacks associated with PVC. At 0.022 mm per meter and per degree Centigrade, its coefficient of linear expansion is less than that of aluminium and PVC, so deterioration at joints and consequent leaks are avoided.
In terms of suitability for low cost construction, zinc guttering was used by Osborne Homes in its Demonstration House at the BRE Innovations Park. In the pursuit of designs which meet the Code for Sustainable Homes, the requirement was for a design which combined exceptional energy efficiency and low cost with use of sustainable materials. The building has a predominance of zinc cladding and roofing, but the guttering also blends well with the lighter coloured timber panelling.
Its use, however, has already extended to mainstream house builders. Persimmon Homes has specified it for 137 properties in the Park Prewett development in Basingstoke, a large proportion of which will be starter homes. By contrast, Herring Homes used the same system for its prestigious development in Church Street, Sutton Courtenay.
In both cases, the use of concealed brackets provides an uninterrupted, ‘floating’ gutter line which blends well with the traditional new brick and tile at one extreme and the weathered and reclaimed building materials at the other. Even against the contrasting clay plain tiles and thatch, the rainwater system provides its own visual distinctiveness.
Far lighter than cast iron, a 2-metre length of 125mm diameter, half-round zinc typically weighs around 2.75 kg compared to 8.3kg and, unlike its traditional counterpart, is not susceptible to impact cracking. It is quicker to fit, products for housing projects such as Pluline 'D; being delivered in kit form. Concealed brackets are simply clipped into the gutter length, a maximum of 400mm apart prior to installation.
Downpipes utilising sleeve connections and self-locking brackets offer similarly convenience. Traditional accessories are available including stop ends, internal and external corners, Y-branches, hopper heads, running outlets, and rainwater diverters. For commercial use, profiles extend to box guttering, the larger gutter lengths and wider profile downpipes being joined by soldered connections.
In terms of sustainability, zinc is fully recyclable and, in the manufacturing process, uses the lowest energy of all the non-ferrous metals. In Western Europe, over 90% of old rolled zinc is recycled so, like lead, a buoyant reclamation market should develop here too. With the trend towards use of natural materials and zinc’s use already as a primary building component, there seems every reason to suggest that specification for guttering will follow a similar trend. Its suitability to functional and radical designs, as well as many historic buildings means that it need not rely on any particular sector of construction. But whether for the mainstream builder or self-builder, it provides an aesthetically pleasing, efficient and sustainable addition to any building.