WASHINGTON – The average rate on 30-year fixed mortgages rose last week for the first time this month, though it remained below 4 percent for the eighth straight week.

Low rates may be contributing to a slow turnaround in the depressed housing market. Still, many who can afford to buy or refinance a home have already done so.

Freddie Mac said Thursday the average rate on 30-year fixed mortgages rose to 3.98 percent last week. That’s up from 3.88 percent the previous week, which was the lowest level on record.

The average rate on 15-year fixed mortgages also rose to 3.24 percent, from 3.17 percent the previous week. Rates on 15-year mortgages hit a record low of 3.16 percent two weeks ago.

For the past three months, the 30-year fixed mortgage rate has hovered near 4 percent. Historically low mortgage rates are among the signs that point to a pickup in the housing market this year.

Sales of previously occupied homes rose in December for a third straight month. Homebuilders are slightly more hopeful because more people are saying they might consider buying this year. And home construction picked up in the final quarter of last year.

Still, new homes fell in December, the Commerce Department said Thursday. About 302,000 new homes were sold last year, making 2011 the worst year for new home sales on records dating to 1963.

High unemployment and scant wage gains have made it more difficult or many people to qualify for loans. Many don’t want to sink money into a home that they fear could lose value over the next few years.

The average rates don’t include extra fees, known as points, which most borrowers must pay to get the lowest rates. One point equals 1 percent of the loan amount.

The average fee for the 30-year loan dipped to 0.7 from 0.8; the average on the 15-year fixed mortgage was unchanged at 0.8.

For five-year adjustable loans, the average rate rose to 2.85 percent from 2.82 percent.