BOSTON — Massachusetts insurance regulators have turned down a bid by the state's largest commercial home insurer to add a deductible for damage caused by ice dams in winter.

The Boston Globe reports that Mapfre USA Corp. asked the Division of Insurance to approve the first-of-its-kind deductible, requiring some homeowners to pay up to $10,000 out-of-pocket for ice dam repairs before coverage was provided.

Ice dams form at roof's edge and prevent melted snow from draining properly, causing damage to interior walls and ceilings. They caused major problems for homeowners during last winter's record snowfall.

Mapfre said it planned to offer the deductible to customers who had multiple ice-dam claims in recent years and were in danger of having their policies canceled.

The state approved overall rate increases for insurers earlier this year.