Materials shortages, unreliable deliveries and skilled labor shortages can all contribute to delays for construction projects and require extensions on insurance.

Projects moving forward but subject to delays often need project extensions on their coverage, according to Bryan Stevenson, head of construction casualty insurance at Axa XL, a division of Axa SA, in Dallas.

“Projects are moving forward, but we ‘re seeing a lot of project extensions — more than we ‘ve ever seen before,” which increases insurance costs, Mr. Stevenson said.

Such extensions can be “challenging” because construction costs and therefore insured values may have increased, said Jim Gloriod, St. Louis-based CEO of Aon Construction Services Group U.S., a division of Aon PLC.

In addition, with property/casualty markets hardening, underwriting conditions may have changed since the inception of the original policy.

“Many of these projects were placed before the market had changed, so now underwriters are looking at those rates changed with the new exposures, and it ‘s causing challenges for the industry,” Mr. Gloriod said.