Brian Robertson, general manger of James Jones Timber Systems, which makes the JJI-Joist, bravely told traders at the London Softwood Club meeting last Thursday how engineered wood products stole a large chunk of their business before they even noticed.

He said if the softwood industry had been quicker to embrace kiln-dried timber in the 1990s with more vigour then the course of events may have been changed. “Perhaps James Jones would not have been selling I-joists,” he added.

“If James Jones had not done anything about it [launching I-joist production] when Trus-Joist came into the market it would have lost a substantial chunk of its business.” I-joists, Mr Robertson said, have now cornered some 75-90% of the intermediate floor market in newbuild houses.

“The UK I-joist market is currently about 16 million linear metres,” he said. “I-joists have probably taken several million metres of solid timber’s market in the 15-18 years of UK I-joist use.”

And increasingly, he said I-joist producers were trying to take a larger share of the roofing market, going head-to-head with TR26 products.

One trader asked about the feasibility of selling I-joists over the counter to builder customers, questioning whether the strength properties were comparable with standard solid sections.

“I have mixed feelings about selling I-joists off-the-shelf to white van man,” said Mr Robertson. “I think the change will come. But we have to be very careful or there will be problems.”

Andrew Caldwell, MBM Forest Products’ project manager, pointed to MBM’s supply of off-the-shelf Louisiana-Pacific I-joists to merchants, saying several traders were successfully selling to builder customers with a product specifically designed as an alternative to UK solid joist sizes.

Mr Robertson predicted another engineered wood product, cross-laminated timber panels, would cause major changes in the way UK construction companies build in the future, particular for commercial and industrial buildings.

“I am sure UK-based CLT production will happen in the not-too-distant future.”