U.S. builders of single-family homes have broken another quarterly record for building permits. They're on the way to their second-best full year in history.

In the 3rd Quarter, one-family builders pulled more than 315,000 permits, eclipsing the previous record of 307,500 established in 1977, research firm U.S. Housing Markets reported in its latest figures just released.

Earlier this year, single-family homebuilders set a records for 1st Quarter and 1st Half activity. Following the record 3rd Quarter, the 903,238 single-family permits issued in the first nine months is a new high for that period.

U.S. Housing Markets is a unit of Hanley-Wood, Inc., the nation's leading publisher of trade journals and magazines for the residential construction and remodeling industries.

Including multifamily permits, said U.S. Housing Markets, authorizations in the 3rd Quarter amounted to 429,168, highest total in the period since 1986.

To surpass the full-year U.S. record that was put on the books in 1978, single-family builders will need to pull nearly 280,000 permits in the 4th Quarter.

That is most unlikely, said Brian Bragg, editor of U.S. Housing Markets. "Even with mortgage rates at affordable levels," Bragg said, "the nation's economy ostensibly is slowing and consumer confidence has been drifting lower. Homebuying probably will not support record construction in the final quarter."

Bragg said the environment has encouraged potential first-time homebuyers.

"Younger people are qualifying much more easily, because rates are so low and they can make the payments," Mr. Bragg said. "Plus, job security is good in a tight market.

Housing permit data are a lead indicator, Bragg said. "Builders have to jump through a lot of hoops to get a permit these days, so they have too much invested in the process to not use it," he said. "When studies use housing starts, they're a month late reporting what we knew by looking at permits issued."

It's a strong probability that 1998 will wind up as the second-biggest year for U.S. single-family construction. If builders pull at least 223,000 one-family permits in the final quarter, they'll beat 1977, which was the second-best year in history. U.S. Housing Markets said builders have exceeded that 4th Quarter volume five straight years.

Breaking the full-year record, which was set in 1978, would take 280,000 in the current quarter. That is unlikely, Bragg said; the "explosive levels" of that year reflected the end of an energy crisis.

But he did not predict a slowdown soon in home building.

"It'll end when interest rates jump back up to 10%, when we're in a recession, or when somebody stops giving us oil," Bragg said. "Until then, there'll always be a reason why you're going to want to move."

U.S. Housing Markets also unveiled its list of the most affordable housing markets. Houston topped that list.

According to U.S Housing Markets, a homeowner in Houston only needed to set aside on average of 24 percent of their income for monthly payments on a typical home purchased in the city last year.

U.S. Housing Markets found that 25 percent of income was needed to maintain the typical homes in Kansas City, Mo., and Indianapolis, while 26 percent of income was needed for monthly payments on the typical home in Tampa Bay and Philadelphia.

In contrast, San Francisco was found to be the least affordable market, with 42 being the average percentage of income needed to be set aside each month to afford its typical home. Los Angeles was next at 41 percent, followed by San Diego at 39 percent, Boston at 38 percent, and Portland, Ore. ,at 37 percent.

U . S . Housing Markets said the Atlanta area will set a single-family permit record for the third year in a row. Residential permits totaled 43,145 through September, 16% more than a year earlier, it reported.

This may not be good news for the area, however. Mike P. Leddy, senior vice president of Crescent Mortgage in Atlanta, said the consensus is that the area is becoming overbuilt. The area, whose current population is around 3.7 million, is gaining 200,000 to 250,000 a year.

"Anytime you have this kind of growth or a time of boom, builders tend to get a little overzealous," Leddy said.

"The time period has already been extended on how long it'll take to absorb new homes in the area," he observed. "It's no surprise: the more houses on the market, the longer time they take to sell."

It's a strong probability that 1998 will wind up as the second-biggest year for U.S. single-family construction. If builders pull at least 223,000 one-family permits in the final quarter, they'll beat 1977, which was the second-best year in history. U.S. Housing Markets said builders have exceeded that 4th Quarter volume five straight years.

The hammer-and-tongs construction frenzy in Texas might be abating somewhat, but volume continues to grow. In the 3rd Quarter, Texas builders exceeded 41,000 permits, pushing their nine-month total above 120,000 -- some 27% higher than a year earlier. That's the highest state total in the nation, about 10,000 ahead of Florida entering the final calendar quarter.

California's building permit numbers are running about 15% ahead of the state's 1997 pace.