Mortgage buyer Freddie Mac says the rate on the 30-year loan increased to 3.62 percent, up from 3.59 percent last week. Three weeks ago, the rate fell to 3.49 percent, the lowest since long-term mortgages began in the 1950s.
The average rate on the 15-year fixed mortgage, a popular refinancing option, rose to 2.88 percent. That's up from 2.84 percent last week and record low of 2.80 percent three weeks ago.
The availability of low rates has lifted home sales higher this year. Home prices have also increased, largely because the supply of homes has shrunk while sales have risen. And builder confidence is at its highest level since March 2007, according to a survey by the National Association of Home Builders.
Homebuilders broke ground on slightly fewer homes in July, down from June when they started homes at the fastest pace since October 2008. Single-family homes and apartments started in July dipped 1.1 percent to a seasonally adjusted annual rate of 746,000, the government said Thursday.
Still, builders in July requested the most building permits since August 2008, suggesting many expect demand for newly built homes to rise in the months ahead.
The pace of home sales remains well below healthy levels, however. Many people are still having difficulty qualifying for home loans or can't afford larger down payments required by banks.
Mortgage rates are low because they tend to track the yield on the 10-year Treasury note. A weaker U.S. economy and uncertainty about how Europe will resolve its debt crisis have led investors to buy more Treasury securities, which are considered safe investments. As demand for Treasurys increase, the yield falls.
To calculate average rates, Freddie Mac surveys lenders across the country on Monday through Wednesday of each week.
The average does not 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 30-year loans was 0.6 point, unchanged from last week. The fee for 15-year loans also held steady at 0.6 point.
The average rate on one-year adjustable rate mortgages rose to 2.69 percent from 2.65 percent last week. The fee for one-year adjustable rate loans was unchanged at 0.4 point.
The average rate on five-year adjustable rate mortgages declined to 2.76 percent from 2.77 percent. The fee was steady at 0.6 point.