What do you do when you have been a paper millionaire during the telecoms and dotcom boom - and then seen it all fade away when the bubble burst? The answer, in the case of one Henley entrepreneur, is to turn to "something more concrete, something more substantial".

Joe Robinson, 42, co-founded Telco-T3 Telecom ten years ago. It eventually became Liberty Surf with a UK turnover of more than £25m. Now the "something more concrete" has turned up in the shape of instant, solid, well-insulated and weatherproof buildings made of, well, concrete.

He said: "With more and more people wanting to work from home, these structures make ideal offices in the garden. They can be clad in any way you like to fit in with their surroundings. And in most cases they don't even need planning permission, because they count as temporary structures.

"They only take four minutes to install and you can take them with you when you move house. All for about £5,000 including VAT."

Mr Robinson has become chief executive of German company Juwel, which has sold 250,000 of the structures in Germany. So far he has opened the 1,500 sq ft offices of what will be Juwel UK on the Highlands Business Park, just outside Henley.

He plans to take on between five and ten workers by the end of this year and to establish a factory, probably in north Oxfordshire, by the beginning of 2010 - by which time there should be between 40 and 50 on the payroll.

Mr Robinson left his final telecoms job with Logica in 2003 and became a Henley house husband, looking after sons aged eight and 12. His change in career came about as a fortuitous by-product of Henley being twinned with Leighlingen, home of Juwel.

He explained: "Through being a school governor here in Henley I met Carol Crowdy of the twinning association and my friendship with the owners of Juwel, Manfred and Dagmar Kruse, took off."

As a German speaker, he hosted a German exchange family in Henley. He has a chalet near Kitzbuhl, Austria, and made friends with the Kruses through a mutual love of ski-ing.

He said: "Manfred knew that I wanted to get back into business and after discussions in 2005 we put together a business plan in 2006."

He is coy about precise investment figures, but setting up an office, complete with showroom, and a factory, not to mention importing a lorry specially adapted for delivering the heavy structures, will clearly run into several hundreds of thousands of pounds.

He said: "I think things have changed. The mantra of the 90s was build it and the business will come afterwards'. Here it is the other way around. We aim to make people aware of these things' existence first, and then build the factory second.

"We have an educational job on our hands here because people don't yet know about this kind of building. They tend to know about either traditional prefabs, or about real building, with nothing in between."

On display are two of the structures, one complete with a solar-powered door.

Mr Robinson said: "The green angle with these structures is that they are simply made in one place and delivered in one journey, using far less energy than usual building operations."

Obviously enough, the subject of Portakabins came up during our conversation. Were they competitors?

Mr Robinson said: "Portakabins are great for their purpose but they are less durable than Juwel structures.

"These prefabricated buildings are much cheaper than using a builder. But, that said, we want to work closely with builders and architects, because these things are great for making home or office extensions and could become parts of the packages they offer."

He added: "I see the market as two sectors: retail and industrial. On the industrial side they can be put together like Lego blocks to make larger spaces for offices, or even classrooms.

"Or they could be garages for MOT work, or for ambulances. Then there is the point that they are very secure, so they could be used for storing valuables at, say, a golf club."

Owners of the company, Manfred and Dagmar Kruse, who started their business in Germany in 1996, spend hours working out delivery systems for their Juwel structures, each weighing more than 16 tonnes.

Now they have six lorries adapted to place the structures very precisely in places where access is restricted.

Mr Robinson said: "Access is our major difficulty, but when our specially adapted system can't be used we can usually still lower a building into place with a traditional crane."

In Germany the structures have been used extensively as garages and in the UK, Mr Robinson reckons they could replace many run-down garages behind blocks of flats.

He said: "We hope to be selling units in thousands, not hundreds, in the near future".

Time will tell, but of course the paradox here is that the concrete structures will further the trend towards home working, which has itself been engendered by a revolution in the communications business - the very business he has left behind.