MONSOON-like weather during the past three months will cost contractors dearly as swamped jobs across the country are delayed.
Civil engineering sites have been hardest hit by downpours.
And industry experts are predicting a deluge of delays following the wettest winter since records began.
A spokesman for civils specialist May Gurney said: There are a lot of problems everywhere.
We have been fairly lucky because of the timing of many of our jobs. But if you are at the earthworks stage the past few months have almost been a write-off.
Contractors hit by the weather will now be negotiating with clients for time extensions.
But the bad weather still costs construction companies dearly because they are not paid for the extra work.
One boss of a south-west civils firm said: Contracts take into account possible delays for bad weather. But you do get caught out by freak conditions. But on the other hand we dont reimburse clients if the sun shines every day of a job.
Companies looking to claim more time from clients, or putting in damage claims to insurance companies, have to get accurate weather statistics to back up their appeals.
Jim Dale, managing director of British Weather Services, said: The enormous amount of rainfall during the past three months has meant we are getting a lot of inquiries from construction companies.
We are here to provide technical back-up for any claims caused by bad weather delays.
Insurance companies are also bracing themselves for a rash of claims from flooded sites.
A spokesman for loss adjuster Thomas Howell said: Hardest-hit have been those sites with sewage and riverworks projects.
A lot of them have been completely flooded and that results in damage and subsequent insurance claims.
The May Gurney spokesman said: The recent weather has definitely been abnormal and that has a knock-on effect throughout the industry.
Lets just hope we have a fairly dry spell now so people can catch up on lost days.