The figure is contained in a Chartered Institute of Building Survey into construction procurement which slams clients for not knowing enough about the whole process.
Clients focussing on lowest cost bids is one of the biggest gripes and the CIOB is urging those procuring work to focus on value for money rather than just price.
The report said: “Unsustainable bids should quickly be identified and refused to be accepted.”
The institute considers “suspicious” bids as those more than 10% lower than the next largest price.
The report adds: “The effects of suicide bidding are felt throughout the supply chain and construction process, with subcontractors feeling the pinch as well as manufacturers and, of course, the client.”