The last bit is wishful thinking perhaps, but a retractable roof – even at a cost of £100,000 – is handy for maximising the few weedy rays of shy sunshine and perfect for impressing people during dull business meetings.
Architects may salivate at the prospect of super-rich clients who can indulge their extravagant fantasies to the full but, in practice, blue-skies thinking is tempered by a long list of tough practical demands. For example, this particular musician has his studio next door to the retractable roof, so it has to operate noiselessly. It has to be totally secure and watertight (so it doesn't leak on to the art collection). And if anyone forgets to close it when a storm is brewing, wind and rain sensors have to do it automatically. It needs to be reliable and, naturally, it has to look good.
In the end, the practice of Sturgis & Company managed to devise an elegant and sophisticated solution using equipment more commonly seen on the factory floor. But getting to that point took months of hard work.
For a start, the architect had to decide what kind of opening roof would work best. A hinged solution was dismissed because of the constraints of an adjacent lift shaft and parapet wall; a sliding roof, on the other hand, fitted the site better. But what kind of sliding roof? The solution the architect finally plumped for was a domed roof, hipped at each end. Half of the domed part slides over the other half to leave an open space of 3.7 × 2.6 m.
The main problem was devising an opening mechanism that would meet the client's tough criteria. Project architect Lesley Turner started off by looking at swimming pool roof systems. After weeks of research and countless phone calls, the breakthrough came in the unique form of a linear drive unit usually used to operate factory machinery.
The discovery of the linear drive unit moved the whole design process forward because, according to Sturgis, it "resolved so many issues". An apparently simple 100 mm square, 3000 mm long box sits on either side of the sliding part of the roof, supporting its 375 kg weight. An integral stainless steel band contained within the box moves the roof silently along its length.
Given the linear drive's original purpose in the zero-defects world of manufacturing, it is perhaps not surprising that the roof's movement can be repeated many times with great accuracy. The mechanism ensures that the roof closes accurately against neoprene seals, compressing them to just the right extent to keep the weather out. The drive unit itself has to be protected from the weather as it sits in the part of the roof that acts as a gutter to drain rainwater. Turner admits: "Having the moving part in the gutter seemed an extreme thing to do."
Finding a company to make the roof proved as challenging as finding an initial design solution. Twelve enquiries were put out during the design stages, but companies were deterred by having to make curved glass to fit the frame, and by the idea of lifting a heavy and delicate roof up six floors onto a difficult site.
Clifford Chapman Metalwork in Newcastle was the only company prepared to take up the challenge. Luckily, the team proved to be dynamic and positive. The design process was very much a two-way, practical experience, with Clifford Chapman making design suggestions all the way through.
First, a mock-up was made and the frame tested to see if it would support the weight of the glass, using people hanging off it. Two formers had to be specially made for the glass as a result of the two different radiuses involved: the outer 10 mm pane of the double-glazing is toughened and the inner 8.8 mm pane is laminated. The panes have a low-emissivity coating to minimise heat loss. After two months' work the roof was ready for installation.
The finished roof was brought by road from Newcastle to London and put in as a single unit, with the glass and moving parts installed afterwards. Two cranes were used to lift the components into position: one for the roof and the second for the glass. After a month, the job was complete.
The roof should operate for years with virtually no maintenance. In fact, lack of use could be the main problem, as the seals could stick over time, but the motor is designed to give an initial push on opening to overcome this potential difficulty.
As for the client, he described it as "a triumph". In fact, he was so delighted that he took everyone down the road to the local pub for a drink – though, given the weather, some of them might have preferred a dip in the heated pool.
