In September homeowner Lin Coppedge jumped at the chance to pay some household debts and reduce her monthly mortgage bill by refinancing her mortgage. What she did not plan on was dealing with the lender-mandated appraisal on her Severna Park house, which came in at $9,000 less than the $179,000 value she needed to secure the new loan.

Like Coppedge, some Washington area homeowners who tried to refinance a mortgage recently have had trouble obtaining a lower-rate loan because of low appraisals on their houses. Specifically, the ratio of the mortgage amount to the home's appraised value, a relationship known as the loan-to-value ratio, was insufficient for lender approval, they said.

In other words, even when a borrower's credit was adequate for a new loan, the home's appraised value sometimes was not enough to protect the lender against default--squashing approval of the loan for the borrower. In recent months, such insufficiencies have been a growing problem for people who have sought to refinance a mortgage, a group of borrowers that has included more than half of loan applicants this year, lenders said.