Having made his millions with his own construction firm, Irishman John Fleming now wants to become the UK's biggest supplier of prefab housing. But he's prepared to make us wait until his system is perfect …
Cork is veiled in soft August rain. The evening streets are deserted, but the bars are humming. We're holed up in Luigi Malone's, a raucous eaterie across the road from the opera house. There are six of us: two from UK contractor Willmott Dixon, two from Irish builder John Fleming Construction and a couple of journalists.

We've just arrived in Ireland to look at a new steel-frame housing system. Called Fusion, it has been developed by John Fleming Construction, and Willmott Dixon is trying it out on a project in Hillingdon, west London. By all accounts it's rather good: fast, accurate and easy to put together on site. Better than anything else on the market, they reckon. Well, they would, wouldn't they? Otherwise they wouldn't have flown us out to see it.

The meal is over now, but the lush Barolo is still in copious flow and the conversation turns to John Fleming, the man behind Fusion. He's a risk-taker, an innovator, a pin-sharp businessman obsessed with improving the building process, they say. He never stops coming up with ideas: in the car, in the bath, midway through board meetings. When he has an idea, he puts it into action. And it usually works. Fleming is something of a genius, they agree.

Fleming, brought up in a tiny West Cork cottage with no running water, is now seriously rich. He owns a spa hotel, a wind farm (he rubs his hands with glee on windy days) and countless other businesses, besides his £80m-turnover building firm. But he's not driven by the money – he does it for the craic.

His latest brainwave is to export his Fusion system across the Irish Sea. This man believes he can become the biggest supplier of housing systems to the UK within a couple of years. He talks of opening four or five high-tech factories around England, serving regional markets, each churning out about 2000 units a year and supplying housebuilders who are increasingly looking to off-site fabrication to get round the skills shortage. If his plan works, Fleming's factories will soon be outstripping those of rival UK steel, timber and volumetric systems.

And he means business: he's just bought the entire contents of the mothballed Vauxhall car plant at Luton. That's millions of pounds worth of state-of-the-art production equipment, including dozens of robots that will soon be reprogrammed to make houses. Now there's ambition. I'm looking forward to meeting Fleming.

Early next morning, nursing sore heads, we arrive at the bland warehouse at Bandon, just outside Cork, that houses the Fusion factory. As we gulp coffee, Robert Clark, Fusion's development director, explains how it all began.

About three years ago, Fleming, who until then specialised in agricultural buildings and civils, decided to capitalise on the Irish housing boom and start building homes. But he soon came up against the skills shortages, poor workmanship and excessive waste that dog the industry. He was convinced there was a better way and felt that off-site fabrication was the answer. So he asked Clark to scour the world for the best product on the market.

"He said go away and look, and don't stop looking till you find it," Clark recalls.

A year and several thousand air miles later, Clark stumbled across a steel roll-forming system in Australia. The process uses computer-controlled machines to turn coils of millimetre-thick steel plate into lightweight beams. These snap together to form panels, which in turn are assembled to make house frames. The machines can spit out the components for a complete house in four hours, to a tolerance of half a millimetre.

Fleming acquired the rights to the process and then spent £10m of his own money improving it. He invented a way of insulating the panels in the factory: a machine resembling a giant sandwich toaster fills the panels with expanded polystyrene. This gives them a thermal and acoustic efficiency that beats UK regulations by a long chalk.

He spent a million on this machine alone.

"It's the only one of its kind in the world," says Clark with pride.

The panels are shipped to site, two houses a lorry, where a gang of four trained operatives can assemble a complete weatherproof shell in two days. The panels are so light – 150 kg on average – they don't need an expensive crane, just a lifting device that the gang operate themselves.

There are lots of building systems around these days, but Fusion has the added advantage of a sophisticated computer-aided design interface. Architects can email their house designs to Fusion's CAD/CAM team, who work out the optimum frame configuration and convert the files into data that can be read by the roll-forming machines.

This means that, unlike other systems, it will churn out non-standard house types just as quickly as large orders of identical units.

It can do almost any odd shape that the architect fancies, except curved walls. The factory operates on a just-in-time basis, meaning panels are made when they are needed rather than when it suits the plant's production schedule. "Some people have tried to optimise factory output, but you need to follow demand," says Clark. "The mega-factory is unlikely because housing is such a localised industry. Our plants will serve a 100-mile radius."

Clark – a Scot – believes Fusion can dominate the UK market because homegrown manufacturers are unwilling to innovate.

We work on the principle that the person who never made a mistake, never made anything

John Fleming

"In Ireland they have a totally different attitude to risk. There's a huge opportunity in prefab but you have to be prepared to put your money down. It all comes back to short-termism."

After a brief tour of the factory floor, where a handful of unskilled workers watch over the rolling machines and casually rivet beams into wall frames, we head back to the offices for chicken sandwiches and our eagerly anticipated meeting with Fleming.

Somehow, you expect a genius to behave … well, like a genius. To exhibit the childlike eccentricity of Albert Einstein, say, or the room-filling flamboyance of Oscar Wilde. Fleming, however, is more like someone you'd find sitting beside you on a charter to Malaga: golf-course tan, bushy brows and big front teeth. The only outward signs of his unstoppable brain are his eyes, which dart like sparrows, alive with curiosity.

He's expecting questions about Fusion but we know everything about that, so I ask him: Why do it? I mean, why would a provincial Irish builder spend £10m on a house factory?

The question catches him out. He freezes for what seems like an eternity, hamster teeth hanging in the air; the room is heavy with nervous anticipation. When his answer comes, it is delivered with a chuckle of the utmost modesty. "I don't know, I honestly don't know," he says in his soft Cork brogue. "Why was I foolish enough back in 1973, when I was 21, to set up the building company? I just get a kick out of doing something new and doing it properly. I don't know where the ideas come from, to be honest."

Fleming is coy about his ambitions for Fusion. He's not in a hurry; he'll perfect the system before conquering the UK: "We'll make all our mistakes here first." But eventually he concedes: "I honestly think that if we can prove our product, the UK market is unlimited. And we're nearly there. I can't see anybody else competing."

The Fusion factory may be state-of-the-art, but the product is unsophisticated. Under current regulations, the frames have to be faced in brick or block skins, so you still need brickies. It does not contain the built-in pipes and cables common in volumetric systems, so you still need tradesmen – although the steel floor joists come with ready-punched holes that allow services to be threaded through.

The main advantage is that the process is entirely predictable. Erection teams can work in any weather and once the weather-tight frame is up, follow-on trades can attend at their leisure. Bricklaying is off the critical path. The precision of the frames means you don't need to bodge the fit-out – in Ireland, they email window dimensions to window-makers, who glaze and paint their products in their factory before shipping them to site. They fit first time, every time. Same with the doors and kitchen units.

Fleming believes the difference between his system and other prefabs is that his company understands the building process; it is not a manufacturer looking for another market for its products. Fusion is designed to make it as easy as possible for the boys on site. "That's where we think we have the advantage. If it's not user-friendly on site, there's no point in having it."

He speaks to his site people constantly, looking for ways to improve the product. For example, he noticed people were putting wall-ties in upside-down, so he patented a new "idiot-proof" tie that can only go in one way. When people complained that the cradle used to transport and store the panels was badly designed, he knocked up a prototype for a better one over a weekend. After hearing reports of kids kicking holes in the white polystyrene panels on a site, he switched the colour to concrete grey and the vandalism stopped. And so on, and so on.

What's refreshing about Fleming and his team is their willingness to admit mistakes. E E Even during this briefing with London journalists, they're openly discussing flaws, brainstorming solutions, sketching improvements on their legal pads. When discussing the way the panels meet at corners, Clark says: "It looks like dog shit."

There are other glitches to iron out. They concede that they need to get architects talking to them earlier on in the process, to help them improve buildability. They haven't yet got British Board of Agrément approval for their insulated roof panels, but they're working on it. They're also not yet allowed to go beyond two storeys, but are confident that BRE will soon approve four floors, and possibly six. "We work on the principle that the person who never made a mistake, never made anything," says Fleming.

A week later, at Willmott Dixon's site in Hillingdon, the frame for the last of 10 houses is being erected. Despite the monsoon conditions of the previous few days, the job is ahead of schedule and the team is delighted.

"I'm very impressed with it so far," says site manager Justin O'Rourke. "The speed of build is incredible. It allows me to get my fixed trades going a week and a half after we start on site. Compare that to traditional build and it's very favourable. Even in comparison to timber frame, you're knocking a couple of weeks off."

Julia Moulder, director of development at client Ealing Family Housing Association, says the system is about 7% more expensive than traditional build and comparable to timber frame – the association is paying a total of £86,000 for the 10 frames. But she adds that price was not the main driver. "We wanted something that would give us shorter site time, more predictability and fewer defects rather than lower price. It's too early to tell whether we've achieved that but we're looking at using it for a bigger job on another site. They feel like a company we ought to be able to do business with."

Tim Carpenter, managing director of Willmott Dixon Housing, is even more enthusiastic. "I came back from Ireland thinking 'eureka'. I can't see a downside. We're probably going to see 25% taken out of the build time. Our waste has almost halved using this; we're hiring half as many skips."

He continues: "The thing that impressed most about Fusion is that R&D seems to go on almost every day. They never stop improving it. For example, stair openings are usually a safety nightmare on sites, but they've made a removable panel that blocks the opening off, with a little hole to put a ladder through. The thought that's gone into it is incredible."

Inside the Fusion factory

  1. The plant uses coils of millimetre-thin steel, plated with zinc and aluminium, which is imported from Australia.
  2. Three roll-forming machines turn the steel into components that snap together to make wall-sized panels. Each piece is printed with a code so the team knows which goes where.
  3. Unskilled workers assemble the panels on the factory floor. The components are fixed together with rivets.
  4. Through this door, external panels are injected with polystyrene insulation in a machine resembling a giant sandwich toaster.