Just as new home construction started rising, a surge in lumber prices is boosting the cost of building as much as $5,000 or more here and nationwide.

The jump in prices is being driven by supply and demand, experts say. Last year, companies reduced production as demand fell, said Paul Jannke, a principal of Forest Economic Advisors LLC of Westford, Mass., which tracks lumber prices. As a result, inventories are low at dealers, and wet weather in the South has kept timber companies from harvesting product.

"The increase in demand for new housing caught everyone -- producers, suppliers and builders -- off guard," said Mitch Wagner, director of purchasing for 84 Lumber Co. in Eighty Four, Washington County. "Everyone expected a slight price increase because we anticipated an increase in new housing production, but not the amount of the increase" Relief may be a month or two away, he said.

The cost of lumber and wood products account for one-third of the costs of materials used to build a home, according to the National Builders Association. A typical 2,400 square-foot home uses almost 14,400 board feet of lumber and 12,400 square feet of structural panels, such as plywood, according to the association.

Plywood prices increased 42 percent since January, according to Wagner. Random Lengths of Eugene, Ore., which publishes lumber prices, reported the cost for 1,000 sheets of all sizes and thickness of OSB (oriented strand board), a plywood alternative, is $474 compared to $244 a year ago. And for 15 different sizes and thickness of 1,000 sheets of framing lumber, it is $367, compared to $210 a year ago.