DAVID DUMIGAN CLAMBERS up an iron ladder on to the windswept roof of Hong Kong's latest monument and pops his head up, almost literally, into the clouds. Billowing, dark tufts drift by overhead, so close you can almost touch them. High-rise blocks stretch into the distance beneath, like miniature sticklebricks, seemingly no longer worthy of the term 'skyscraper'; Hong Kong's most famous vantage point, the Peak Tower, is at eye level and, in the distance, is the blue-grey sea of Repulse Bay to the south and the rolling hills of Kowloon to the north. It's a breathtaking sight. Standing 413 metres above the ground everything appears small. Except, that is for Dumigan, posing proudly at the summit of Two IFC, the city's tallest building and one of the highest in the world. 'We have created a landmark for the city,' he declares. 'Hong Kong wouldn't be Hong Kong without high-rise buildings.' Wind tousles Dumigan's hair, but nothing appears to ruffle him as he climbs the building's lightning rod to be photographed. Unflappability is a quality Dumigan has needed these past eight years. He has overseen construction of a giant monolith dwarfed only by the 442-metre Sears Tower in Chicago and the 452-metre Petronas Towers in Kuala Lumpur. The tallest building Dumigan had previously worked on was the 38-storey One IFC, which was completed in 1998 . 'It's very satisfying to see it completed,' says the Ulsterman who has lived in Hong Kong for 21 years. Not only is it completed, but it was built in three-and-a-half years, a schedule only made possible by meticulous planning. Originally, Two IFC was envisaged as two 200-metre structures similar to One IFC, but in 1996 a consortium led by Sun Hung Kai Properties and Henderson Land Development - Central Waterfront Project Management, which Dumigan heads - won the right to build it and suggested 'plonking one on top of the other' to create an 88-storey landmark. Dumigan admits planning authorities took some convincing, but new plans included the doubling of the amount of open space for public use to 1.4 hectares and helped swing the decision their way. 'We persuaded them because we're a landmark building and also because we have so much open space. It was a trade-off,' says Dumigan. Prospective tenants were asked what they wanted from such a building and the answer was clear: maximise the views. World-renowned architect Cesar Pelli designed a building with a concrete core, meaning just eight columns - or 'megacolumns' - were required on the periphery, far fewer than those at other world giants such as Sears Tower or Hong Kong's Central Plaza. 'The columns are 24 metres apart, so the views are relatively unobstructed,' Dumigan says. While the plans were being drawn up, Dumigan's team set about working out the nuts and bolts of just how to erect such a building. The financial crisis had stalled work on the development until that start of 2000, but once approval was given the aim was to complete it at breakneck speed. Key to the plan was to build a 61.5-metre-wide and 38-metre-deep cofferdam on top of the bedrock to enable the construction of the six-storey basement shopping mall and MTR station beneath while the skyscraper was built above. One million cubic metres of soil were dug out to make space for the basement, which was constructed from the top down, saving a year in construction time. Building One IFC along the same design was another time-saving advantage. The engineers also visited Petronas Towers, Sears Tower and the World Trade Centre in New York to see how they had been built. Surprisingly, Dumigan says, they learned most from the oldest skyscraper on their list, the Empire State Building in New York, completed in 1931. 'They kept meticulous records, especially about how to handle the logistics,' he says. A variety of techniques enabled them to make fast progress. A $16-million jetty was built next to the Outlying Islands ferry piers, enabling the 800-truck loads of soil to be carried daily from the site to be dumped straight on to a barge and taken away by sea. The jetty was also used to ship in prefabricated glass wall panels and steel structures weighing up to 25 tonnes from southern China. 'Without that we would have needed 5,000 people on site,' says Dumigan, 'and would have taken years longer.' The core was made from concrete pumped from a cement-making plant built on site. According to Dumigan, the building balances like a skier. The core is the skier while the megacolumns act like ski poles, linked by three sets of 'arms' - support floors - at different levels of the building. All this progress was nearly for nothing. On September 11, 2001 the shockwaves of the New York Twin Towers attacks reverberated around the world. For Dumigan, the horror was compounded by the possible implications for his project. 'Everyone was panicking,' he recalls. 'We did a complete review of our design, which involved Les Robinson, an adviser to the initial World Trade Centre.' A series of catastrophe tests proved it was far better prepared to withstand a terrorist airplane attack than the 35-year-old Twin Towers. For a start, buildings in Hong Kong are designed to withstand the highest wind speeds in the world, 50 per cent stronger than those in New York. 'They are strong enough to withstand the mega typhoon which happens every 50 years - or may never happen,' says Dumigan. Two IFC has been built to last 120 years, but could stand for centuries longer, according to Dumigan. It has already earned its place in celluloid history. Local film star Aaron Kwok Fu-shing filmed a scene on the roof, while stuntmen working on the Angelina Jolie film, Tomb Raider 2, paraglided off the 84th floor. But this is the only view from the tower that most people will get. There is no public viewing platform or restaurant. 'We thought about it, but it was prohibitively expensive,' says Dumigan. Besides, he says, the bankers who will inhabit the 21st-century monolith 'wouldn't want to get mixed up with the public coming up to have a look'. Bankers, says Dumigan, are prepared to pay top-dollar for the top floors. The Monetary Authority has taken 14 floors, including the top 12. But even this privilege won't last. On the roof of Two IFC, Dumigan points across the harbour to the Kowloon Station Project opposite. By 2008 or 2009, a 480-metre, 102-storey commercial building, Union Square, is scheduled for completion. It will stand sentry along with Two IFC, an imposing gateway into the harbour from the West. Union Square will be the world's tallest building, unless the 677-metre Centre of India Tower in Katangi, Madhya Pradesh, is completed first. Either way, those at the top will be able to look down on their neighbours at Two IFC. In the tall building business, no one stays at the top for long. tower-topping statistics The fastest of the 62 lifts at Two IFC whisks passengers up 88 floors in an ear-popping 60 seconds. That means an average speed of about 15 miles per hour. The average time it takes to walk down the building's 2,500 steps is 23 minutes. Last month Island School student James Stansfield, 18, climbed up them in just 22 minutes. Counting the lightning rod, the building is 420 metres tall - making it the world's third tallest building. The top floor is 400 metres above street level. To make room for the basement, workers dug out one billion cubic metres of soil - enough to fill 500,000 Olympic-sized swimming pools. Construction of Two IFC required 112,000 cubic metres of concrete, which would be enough to fill 210 double decker buses, and 28,000 tonnes of steel - enough to make 3.4 billion soft drinks cans.