Rates on long-term mortgages edged up this week as the economy showed signs it is still working through a rough patch.

The average interest rate on a fixed-rate 30-year mortgage was 5.85 percent for the week ending April 11, Freddie Mac said Thursday in its weekly nationwide survey. Last week the rate was 5.79 percent.

A month ago, 30-year rates fell to a record 5.61 percent, the lowest since Freddie Mac began tracking 30-year mortgages in 1971.

Records that go back farther indicate that the rate was the lowest since the early 1960s.

For 15-year fixed-rate mortgages, a popular option for refinancing, rates crept up to 5.17 percent this week, compared with 5.06 percent last week.

For one-year adjustable mortgages, rates were 3.80 percent, compared with 3.82 percent in the previous week.

This week's mortgage rates do not include add-on fees known as points. Each loan type carried an average fee of 0.6 point this week.

A year ago, rates on 30-year mortgages averaged 6.99 percent, 15-year mortgages were 6.49 percent and one-year adjustable mortgages stood at 5.00 percent.

AWARDS . . . Architect I.M. Pei won the National Building Museum's Henry C. Turner Prize for innovation in construction technology. Pei's use of technology in projects that include the National Gallery of Art's east wing, Hong Kong's Bank of China tower and the Miho Museum in Japan is to be discussed from 7:30 p.m. to 9 p.m. Tuesday at the National Building Museum, 401 F St. NW, Washington. The panel discussion, moderated by former PBS news commentator Robin McNeil, is preceded by a reception at 6:30 p.m. Tickets are $20, with member and student discounts; registration is required. Call 202-272-2448 for information; Web site: www.nbm.org.

EVENTS . . . "Big & Green" lectures are scheduled from 6:30 p.m. to 8 p.m. Monday and Thursday at the National Building Museum, 401 F St. NW, Washington. The Monday lecture, "Green Building Goes Outdoors," is to be led by J. William Thompson, editor of Landscapte Architecture magazine, and Kim Sorvig. Thompson also is to sign his book, "Sustainable Landscape Construction: A Guide to Green Building Outdoors." The Thursday lecture, "The 3-D City," features Winy Maas, principal of the Rotterdam-based firm MVRDV. The fee for each lecture is $17, with member and student discounts; registration required. Call 202-272-2448 for information; Web site: www.nbm.org