Corus gambles on Constellation
By the time you read this, Rodney Rice will be gloating – or eating humble pie. The Corus Colors product development manager is determined to give his latest baby, a shimmery two-tone cladding called Constellation, a head start. So he has installed it on the high-profile Living Tomorrow building, the centrepiece of a five-year future lifestyles exhibition in Amsterdam. If that doesn’t impress specifiers, Corus will kill it off there and then – and kiss goodbye to a return on its big-bucks sponsorship of the event. Seeing is believing
While Constellation looks suitably extraordinary for the wackily shaped Living Tomorrow building and the welcome-to-the-future devices and systems that will inhabit it, Rice has also engineered the cladding to be a mainstream product with no nasty installation surprises. In the case of Constellation, which looks silver or blueish depending on the angle you view it from, Rice reckons that seeing is believing: “It can take years for architects to get their heads around an unseen product. This way, we’ve got it on a building before launching it, short-circuiting what is otherwise a very slow process.” A showcase for what homes and offices could be like five years from now, the Amsterdam edition of Living Tomorrow is a Dan Dare-type construction that looks like a giant hand-held dustbuster. A silvery aluminium cladding with three Adidas-like glazing stripes covers the 50m-long lower building while the attached five-storey tower is encased in Corus Colors’ silvery-blue Constellation. In development, Rice’s big challenge was to exercise restraint. “It couldn’t be too loud, fragile or expensive,” he says. “If it’s too difficult to specify, it frightens the horses.” The final product has an easy-to-specify grey finish with an added colour trend that from one angle appears standard corporate silver but from another incorporates a blue flash. Eye of the beholder
“It’s a subtle shimmer rather than a flip,” says Rice, “so it’s not too scary.” What is scary is giving the go-ahead for 2000m2 of new cladding for a prestigious five-storey tower on the basis of tile-sized samples. “It’s a scale effect and on a large elevation it will look great. After all, we’re going from 6in samples to a 40m-high tower with curves,” he says. To help the sheet metal cladding fit the curves of the Living Tomorrow tower, Corus profiler SAB-profiel is supplying Constellation in relatively short 3m-long panels. Smaller sheets are easier to bend and allow the installer to make corrections more easily. Constellation’s low-profile thickness of just 19mm also helps in bending the sheets – a useful attribute when you’re wrapping metal around a building that curves in three dimensions.
Enquiry number 200
Sustainable system wards off heavy weather
The door of the site hut opened and in walked a tenant of the hard-to-let council-owned tower block. The problem? There wasn’t one. The builders had nearly finished recladding the block, and she’d come along to say thank you: for the first time in 15 years she no longer had to mop up the condensation dripping down the windows of her flat every morning. That was back in 1988. Having got it right first time round, architect Michael Brodie has stuck with the same refurb system on a total of 15 concrete tower blocks in Croydon (work on the last two began this summer), overcladding them with an insulated aluminium rainscreen. Built of large prefab concrete panels in the 1960s, the 11-storey towers lost heat to the outside as fast as they gained rainwater on the inside. With single-glazed windows and one inch of polystyrene separating the inner concrete leaf from the outer, the blocks were damp from water penetration and condensation. Nothing the council tried had worked. Masking out the joints, putting flashing over them, drylining the internal walls – none of it could overcome the suction effect which pulled wind and rain across the walls of the blocks and into the buildings. Brodie concluded that conventional means could never solve the problem and looked around for a more radical treatment. He found it on the Continent, where overcladding residential buildings was an accepted refurbishment technology at the time. Bright ideas
Since refurbishing the first of the Wates tower blocks (as the high-rises are known, after the company that put them up), Brodie hasn’t looked back. The amount of mineral wool insulation used in each successive block has got steadily thicker over the years and various energy recovery schemes have been tried out, but the fundamentals remain the same. An aluminium hook-on rainscreen breaks up the force of the wind so that it can’t blow large quantities of moisture across the ventilated cavity and into the building, while the mineral wool insulation on the other side of the cavity is an inert material that can’t become saturated. The PVF2 coating on the EDM Spanwall 3mm-thick rainscreen has a 25-year guarantee, and only needs washing down every few years. Brodie says it’s a sustainable system as the non-corroding aluminium panels can be unhooked and recoated when necessary. It takes around six months to refurbish each of the blocks, which remain occupied during that time. Drilling holes to take the brackets for the rainscreen to hook on is noisy, but only for those flats within earshot. The tenants get to choose the colour scheme, and Brodie overclad the first blocks in contrasting terracotta and cream. “Then one tenant, a classic racing car buff, wanted the cream and British racing green combination, and talked the residents’ association into agreement. Every block since has gone for green and cream.” Colour co-ordination extends to the central refuse shoots that run down each block. Brodie clad these with bespoke curved panels and built up the roof parapet to look like an extra floor, masking the plant room with rainscreen and louvres. Repeat success
Brodie says refurbishing the two-bedroom blocks cost £868,000 each, with the three-bedroom blocks costing £950,000, although these figures exclude prelims – a presumably substantial amount given Brodie’s emphasis on the importance of upfront design. Was it worth it? Croydon Council clearly thinks so, having repeatedly come back over 15 years with finance for one block after the other. Formerly hard to let, the now warm and dry blocks are sought after. The only water penetration Brodie has recorded in all that time was the result of poorly fixed insulation – right at the point where the original concrete had fractured.
Enquiry number 201
Source
Construction Manager
No comments yet