Forget what you've heard about a glut of new houses on the market.

For three years, Dallas-Fort Worth builders have sold more homes than they have constructed. So the inventory of finished new houses has fallen so low that homebuyers may encounter a shortage when next year's market kicks off.

"For homebuilders to maintain their current sales pace, they are going to have to start 30 or maybe 40 percent more homes than they are starting today," said David Brown, who heads the Dallas office of real estate analysis firm Metrostudy Inc.

"There continues to be a demand for new homes, and we are not adding as much supply."

During the last two years, builders in North Texas have sold almost 13,000 more houses than they have started.

That's caused inventory to drop below 5,000 units – about a three-month supply.

By comparison, there's more than a seven-month supply of new homes for sale in the U.S. as a whole.

And that's after the federal tax credit for first-time homebuyers pulled thousands of new homes off the market, builders report.

"Actually, Dallas never had a severe oversupply of new homes as reported nationally – some overage, but not severe," said Dr. James Gaines, an economist with the Real Estate Center at Texas A&M University.

"Given there's been relatively little to no new construction and the tax credit and price declines have spurred purchases of the existing inventory of new properties, it's not surprising that the total inventory is low."

But having demand that's stronger than supply doesn't mean the housing industry will respond with more construction.

"I think the prospects for builders to get funding for new-home construction are severely limited, bordering on nonexistent," Gaines said. "Some of the local regional banks that don't have significant existing exposure may be willing, but what we're hearing is that most of the major institutions don't want to do anything."

Award-winning Texas homebuilder Bill Darling knows he could move more houses if he just had them to sell.

"We should have significantly more inventory, because people are asking for it," said Darling, whose Frisco-based Darling Homes was recently rated the top D-FW area builder by consumer research firm J.D. Power & Associates. "But with our credit lines constrained, it makes it difficult to start houses."

Darling estimates that almost 70 percent of what he builds is already sold, leaving just a few dozen speculative homes to market.

"In other parts of the country, there still is too much new-home inventory," he said. "But there is no question that the lack of inventory has hampered our business plan this year."

Tim Jackson, a Collin County custom builder who is president of the Home Builders Association of Greater Dallas, predicts new-home prices will rise next year unless starts increase.

"We just can't get the funding to start new houses," Jackson said. "I'm fortunate to have a good relationship with a local lender, and they allowed me to start a speculative home four or five months ago.

"But I doubt they would allow me to start another one," he said. "Even if we have a customer who wants to build, they are oftentimes finding it difficult to find construction financing, too."

Some large corporate builders are increasing their starts to meet demand – particularly for homes priced below $250,000.

During the third quarter, D-FW home starts rose by about 1,000 from the previous quarter, according to the latest statistics from Residential Strategies Inc.

Much of that increase came from D-FW's biggest homebuilder, Fort Worth-based D.R. Horton Inc., which started 844 houses here in the third quarter, analyst Ted Wilson said.

Wilson said new-home sales in North Texas – which are down about 35 percent this year – will continue to fall until building picks up.

"That usually occurs a couple of quarters after the official bottom in the annual start rate," he said.

Builders are hoping that bottom comes late this year or early next year.