WASHINGTON — Record demand and rainfall have led to record construction backups for the nation’s top home builders, meaning longer waits for buyers trying to get into new houses.

The number of homes contracted for but not yet finished by the nation’s leading public builders, known as the construction backlog, was 24.2 percent higher in the third quarter of 2003 than in the same period of the previous year, according to Robert Curran, New York-based home-building analyst for Fitch Ratings. And the 2002 quarter was a record.

Nationwide, deliveries are taking about six months from the time a house is ordered, Curran said. But in hot markets, "that could be closer to eight or nine months."

"Most of corporate America would give their eyeteeth to see a backlog up so high," Curran said. But "what it tells a consumer is that … it may take a bit longer for their house to be delivered."

Much of the delay is due to the incredible demand that arose when mortgage rates dropped to 45-year lows this year, say housing experts. Existing and new-home sales are on a pace to set records. And Tuesday, the Commerce Department reported that the pace of housing starts rose to its strongest since February 1984.

Michael Carliner, an economist at the National Association of Home Builders, said the ratio of backlog to sales is about the same as a year ago, but "since sales are at record levels, the total backlog is larger." He estimates the backlog nationally for the nation’s thousands of builders at about 4 1/2 months.

Local builders say miserable weather has stretched out delivery dates even beyond what was caused by the demand for housing.

"This is the worst weather we’ve seen in years, no question about it," said Cory DeSpain, regional vice president for luxury-home builder Toll Brothers. "It’s very difficult to work in the rain, very difficult to work in the snow."

"We’ve been fighting our way through it, at quite a bit of cost," DeSpain said. The company has added workers and hours, and even put tents over houses to keep construction going.

Toll Brothers is also importing building techniques used in traditionally wet climates such as Seattle, DeSpain said. That includes using "soil cement," a mixture of concrete and soil, to make a sturdier base for paving. "If we don’t get the pavement down, we can’t start the houses and then the spring deliveries will be delayed," he said.

Nature’s contribution to the delays began with unexpectedly brutal snowstorms at the beginning of the year. An overly wet spring lasted well into summer, making it difficult to pour foundations and pave roads.

September brought several severe windstorms and then Hurricane Isabel to the East Coast. Power was knocked for two or three weeks in many communities, throwing off electric utilities’ schedules for hooking up new communities.