Manufacturers will find themselves involved in court battles over selling the wrong products, when the construction sector feels the pinch from new building regulations on energy efficiency in April, according to the Construction Products Association.
Industry affairs director John Tebbit warned that the supply chain does not have enough time to prepare for amendments to Parts F and L on ventilation and fuel conservation, following a government announcement last week.
He said the new rules were delayed six months while the government made a decision on "consequential improvements" to buildings.
Tebbit described the timing of the new regulations as an "unmitigated disaster".
He said the industry will not have enough time to accommodate SBEM, new software essential to determining the energy efficiency of non-domestic buildings.
"Projects will be delayed, people will be sued and it will be an unmitigated disaster. The only people to make any money off it will be the lawyers," Tebbit said.
"It's a complete and abject failure at ministerial and departmental level," he added.
The new rules depend on software developed by the Building Research Establishment (BRE), the second test version of which is expected to be released this week. The industry will have one month to test the software and submit comments to the BRE.
Tebbit said the earliest date for the SBEM's final version will be in December.
However, he said the software will need further modifications, and contractors will not have enough time to learn how to use it.
Tebbit said: "This is not going to be a sophisticated piece of software. You can't pour the CAD design data into it. No one is going to actually know how to check the building for compliance.
"What if your package says it complies and the building officer's package says it doesn't?"
He said the government is over a barrel. If it delays rules on non-domestic buildings, and gives the go-ahead for testing domestic projects, it will cause problems for suppliers to mixed-use developments.
Tebbit said: "All that will happen is that people will use the old system and just bluff it."