The Yorks based firm said orders are also “exceptionally strong”.
The increase is the highest rate of improvement in enquiries reported by Birch since the start of the recession and the company said they contradict latest depressing official figures on consruction output.
Managing director Chris Birch said: “We hope that this fledgling recovery is the start of a more optimistic future for the industry.
“There certainly seems to be more confidence from our customer base that now is the time to start investing in their buildings and constructing new facilities.
“It is still proving a challenge to secure opportunities with competition high in the region but our record of performance as a contractor and our financial robustness is why customers are choosing William Birch”
Construction director Paul Goyea is still cautious about the state of the market.
He said: “Whilst we are delighted that enquiry levels have increased so dramatically we know how fragile the construction industry currently is – it is difficult to plan in times like this but for now we are enjoying the rush of enquiries and working hard to convert many of them into orders.”