It has raised concerns with government about the affect staff shortages are placing on an industry already balancing unprecedented demand.

“We are currently facing the biggest demand for building products we have seen in more than 30 years,” said John Newcomb, CEO.

“We are already struggling with the labour we have to meet that requirement. Now, with many staff going into isolation after being pinged by the NHS Covid app, builders’ merchants, and building materials suppliers and manufacturers, are facing a huge challenge.

“The past two to four weeks have been described as the most challenging of the entire pandemic by some members.

“Our concern is that lead times will be pushed even further back and we could see disruption, now and later down the line.

“The supply chain is extremely stretched on all fronts.

“We are feeding all our data back to the government as they establish a complete picture of the situation. Hopefully a solution can be achieved. An ideal situation would be to pull the exemption date forward for the sector.”

The BMF represents 760 members, who together have combined sales of £39bn and employ over 207,000 people in the building materials industry.

“We are disappointed that our colleagues have not been included on the list of workers that can be made exempt from full self-isolation if they are alerted by NHS test and trace,” said Frank Elkins, group chief operating officer for Travis Perkins plc.

“Having worked hard to put in place measures that safeguard our staff while they have played such a vital role in helping to maintain essential services that are so crucial to keeping us all dry, warm, safe and secure, we urge the government to look again at the broader construction supply chain and its importance to the country at large.”

“Currently, 15% of our workforce have been affected by self-isolation this week. None of them have tested positive for Covid-19,” added Paul Bence, managing director of Cheltenham-based independent builders’ merchant George Bence Group.

“With it also being staff holiday season, we have been operating on a skeleton staff basis in many areas.”