Mr Pannell was speaking at the TRA’s Low Carbon debate, along with Stuart Harker, Timber Trade Federation sustainability manager, and David Hopkins, head of external affairs at Wood for Good.
Mr Pannell said many people were asking whether the government’s 2016 target for all new homes to be "zero carbon" was actually going to happen.
"It’s getting very tight," he said, adding that he had warned ministers, including housing minister Mark Prisk, of the situation.
Mr Pannell, who has held senior roles at Taylor Wimpey, said the Zero Carbon Hub was overseeing a new project DvAB (Designed v AS-Built) – launched on March 6, with £380,000 of government grant funding.
He said the project would examine the gap between the stated energy efficiency in new house designs and the actual energy-efficient performance when tested on completion.
Mr Pannell said one project had tested 16 new houses, all of which had failed to achieve the designed performance, with one house testing at 300% below the stated performance.
On the roofing front, he said the big three housebuilders were looking increasingly at prefabricated roof systems for ease of delivery.
Stuart Harker told TRA members of the increasing importance of Environmental Product Declarations – which provide verified and comparable information about the environmental impact of a product.
"This is the way forward for construction products," he said. "I spoke to one contractor the other day who said they are only going to use a supply chain that is on board with this.
Mr Harker said the timber sector also needed to familiarise itself with Building Information Modelling (BIM) – digital representations of physical and functional characteristics of buildings.
Meanwhile, David Hopkins described the carbon debate as a massive challenge and opportunity for the timber industry. Becoming green low carbon solutions providers, rather than just supplying a product, was key.
He said that, compared with competitor materials, the timber industry had been complacent about getting its low carbon information out to the build sector.
But Wood for Good’s Wood First campaign is encouraging local authorities to use more wood and the industry’s Growing Cities initiative is to target major urban centres, telling the whole story of wood’s benefits and highlighting case studies.
In a time of open debate and questions, Stuart Harker suggested fabricators look at the possibility of being able to manufacture south-facing monopitch roofs.
David Hopkins encouraged fabricators to take an innovative approach, citing the example of B&K Structures, which diversified from steel to timber structures when it saw the build and sustainability benefits of engineered timber construction.
"If we had 10 more companies like B&K we would see a lot more timber being used and sold," he said.
One TRA member said the industry needed a single message for the contractor client audience, as contractors sometimes had trouble in specifying timber, especially with the plethora of different messages, products and certification/regulation.
Rob Pannell said both Taylor Wimpey and Persimmon believed strongly in the efficiencies of timber frame construction, through their respective timber frame operations – Prestoplan and Space4.
When the housebuilding market picked up, he added, there would be even further emphasis on the build method.