U.S. builders started work in August on the most single-family homes in six months and requested permits to construct even more in future months. The figures suggest housing remains a driver of economic growth despite higher mortgage rates.

Construction of single-family homes started rose 7 percent last month to a seasonally adjusted annual rate of 628,000, the Commerce Department said Wednesday. That's the fastest rate since February. And builders sought 627,000 permits to construct future single-family homes, 3 percent more than July and the best pace since May 2008.

Overall, builders broke ground last month on houses and apartments at an annual rate of 891,000. That's up from a rate of 883,000 the previous month. The gain in single-family homes was offset by a decline in volatile demand for apartments.

Total permits fell to a rate of 918,000 from 954,000 in July, also because of a decline in apartments.

Still, several economists noted that single-family homes represent the bulk of the market. They made up 70 percent of homes started in August. Ted Wieseman, an economist at Morgan Stanley, said their value is two to three times that of an apartment building. That suggests residential construction should boost economic growth again in the July-September quarter.

"The fact that the trend in single-family starts and permits continues to improve ... supports our view that construction activity will continue to increase through year end," said Joseph LaVorgna, an economist at Deutsche Bank.

Housing starts are 19 percent higher than a year ago. The housing market has been recovering steadily over the past year, helped by lower mortgage rates and steady job growth. The gains have contributed to economic growth at a time when consumers and businesses have spent more cautiously.

But mortgage rates have risen more than a full percentage point since early May. Some economists say higher rates may be starting to slow the recovery's momentum. In July, new-home sales plummeted to the lowest level in nine months.

Mortgage rates could rise even further if the Federal Reserve decides later Wednesday to slow its $85 billion a month bond purchase program. Most economists expect the Fed will announce that it will reduce its purchases by $10 billion. The bond purchases have kept long-term interest rates low.

The average fixed rate on a 30-year mortgage was 4.57 percent last week. That's near the highest level in two years. Still, rates remain low by historical standards. And most economists expect the housing recovery to withstand the increase in borrowing costs.

Homebuilder confidence remained at its highest level in nearly eight years in September, according to a survey by the National Association of Home Builders. But builders are starting to worry that sales may slow in the coming months if rates keep rising, the survey found.

Though new homes represent only a fraction of the housing market, they have an outsize impact on the economy. Each home built creates an average of three jobs for a year and generates about $90,000 in tax revenue, according to NAHB statistics.