Project architect Martin Gray of ECE Architecture discusses best practice design for zinc roofing and cladding at the Lady Bee Enterprise Centre in Shoreham with Architecture Today’s Technical Editor John Ramshaw
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Lightweight industrial buildings have had a long and rich association with architectural invention and development over the last century. Today however, these types of structure are more often than not erected quickly and cheaply with minimal aesthetic value and poor environmental credentials. A notable exception is the recently completed Lady Bee Enterprise Centre at Shoreham Port in West Sussex.
Designed by ECE Architecture, this sustainable and visually striking development comprises three quayside blocks containing 14 B1 and B8 commercial units. Central to the success of the project in both aesthetic and performance terms is the use of elZinc cladding and roofing from SIG Zinc & Copper. Project architect Martin Gray, in discussion with Architecture Today’s Technical Editor John Ramshaw, explains why zinc was the preferred material choice, how the specification and detail design processes evolved, as well as issues relating to onsite installation and guarantees.
How did the project come about and what is the concept?
The project was commissioned by Shoreham Port Authority and is part of a larger initiative aimed at attracting small businesses to the local area. Conceived as a flagship development, the scheme not only had to be flexible and well suited to the needs of SME’s, but also achieve a BREEAM Very Good rating. The latter was particularly important in light of Shoreham Port’s carbon neutral and EcoPort status. We worked closely with environmental consultant Delta Green to incorporate both passive and active sustainable technologies, including high levels of insulation, photovoltaics and EV charging points. Among the most important and striking aspects of the scheme are the saw-tooth roofs. Intended to evoke waveforms, the zinc-clad profiles utilise both north lights and PV panels (fitted to the north and south-facing slopes respectively) to maximise daylighting and energy generation.
Why was zinc chosen over other types of metal roofing and cladding for the project?
When specified with the correct coatings, zinc is ideal for coastal locations as it is incredibly resistant to salt and other pollutants. Furthermore, it has ‘self healing’ properties when scratched, does not degrade in UV light, and is easy to form. It’s malleability allowed us to use the same material for all aspects of the roof and cladding, which helped with design and detail continuity.
In addition to its obvious aesthetic qualities, zinc has excellent environmental credentials. It requires much less energy to produce than steel, copper and aluminium, due to its low melting point, and is completely recyclable. Zinc also has low toxicity levels, meaning that it has a clear water run-off and will not damage the soil and ground water supply.
Why did you favour SIG Zinc & Copper over other zinc manufacturers, and why in particular elZinc products?
ECE have used SIG Zinc & Copper products on a number of projects over the years and have always received a good service from the company in terms of technical support, office visits from representatives at short notice, and the quick delivery of samples. We chose elZinc Advance because it is specially designed for coastal environments. The product incorporates a protective coating that prevents salt damage by enabling the mineral to be washed off the surface of the metal. This appealed to our client and us, as it guaranteed the future appearance and longevity of the cladding.
elZinc was also favoured for reasons of cost effectiveness, colour choice and the availability of shingle cladding. The latter is employed on the east and west elevations in reference to the local fishing industry. By contrast, the north and south elevations are clad with standing seam elZinc. This forms a continuation of the roof profile, defining the edge to the site and evoking the hulls of metal ships.
In terms of colour, we chose elZinc Slate for the standing seam roofing, and elZinc Crystall for the fish scale inspired shingles. The latter has an iridescent quality, which allows the facades to change colour at different times of the day and reflect the nearby dock water. A gold-coloured shingle was initially considered, but it was felt that this would not suit the port’s brand identity, and could be a distraction to boats and ships using the marina.
How did you approach the specification and detail design processes?
The detail design and specification of the cladding and roofing was developed in collaboration with the roofing contractor, Kingsley Specialist Roofing, and SIG Zinc & Copper, as part of a Design & Build contract. Originally, the cladding construction was conceived as a board and rail system. However, this was eschewed in favour of high-performance composite panels for reasons of improved thermal and fire performance, airtightness, space saving, speed of installation, and surface flatness. Early consultation with both Kingsley and SIG Zinc & Copper helped to ensure that the most effective construction method was chosen in respect of performance and cost.
What is the material build-up for the zinc-clad envelope?
From inside to out, the build-up comprises structural steelwork (400mm), purlins and sheeting rails (280mm), composite panels (85mm), breather membrane, standing-seam roof or zinc shingles (32-70mm).
What were the main technical challenges and how did you overcome them?
There are a number of bespoke flashings, valley gutters and eaves profiles, which were detailed and then folded on site. This is another benefit for using zinc over other materials. We also needed to set out the shingle cladding angle parallel to the roof profile, which is a key design feature. The subcontractor set up a sample section on the building’s composite cladding panel. We then reviewed this and made adjustments onsite before progressing with the final installation.
Concealed gutters combined with an internal drainage system were among the more complex aspects of the detailing process – the aim being to ensure a ‘clean’ external aesthetic, free from downpipes. One of the advantages of working with SIG Zinc & Copper was that its sister company SIG Design & Technology was able to supply Armourplan single ply membrane for the gutters. The company was also able to supply the composite panels, enabling it to provide a 30-year system-backed warranty for the entire roofing and cladding package.
How was the roofing/cladding installed on site, how was quality maintained, and how long did it take to install?
The roof and cladding was installed by Kingsley Specialist Roofing under the guidance of the main contractor. The site was very compact, so quality management from the main contractor was easy to achieve. SIG Zinc & Copper’s business development manager Paul Cousins provided quality control through regular site visits. This ensured that the installation was carried out correctly and in accordance with the specification. A site report with photos documenting the entire process was then issued to ECE Architecture and the client.
ECE also had a number of client and design team meetings on site to review the works and the progress of the project. We probably visited the site more than is normally required, partly due to its proximity to the office, but also because we wanted provide the best technical support we could for the main contractor.
With regards to the installation, the roof had to be finished first in order to fix the PV panels ahead of a tariff cut off date. This was six months into the 12-month construction programme. The zinc cladding was then installed following this period and took around two months to complete.
For more information on zinc cladding and roofing visit www.sigzincandcopper.co.uk.