PORTLAND – A building boom in China fed by its expanding economy and reconstruction of the hurricane-damaged Gulf Coast are contributing to shortages of steel, concrete and other materials used in construction. Effects of the increased demand are being felt in Maine.

“It’s Katrina, it’s China, it’s all going into the mix,” said Paul Bradbury, facilities engineer for the Portland International Jetport, which is moving ahead with plans for a new parking garage.

Supplies are short and prices are up for PVC pipe, which is used in plumbing, and roofing membranes, both made from petroleum products. Materials including steel and concrete are hard to come by because of demands in China and along America’s Gulf Coast. Plywood and other wood products also have been in short supply.

The rising prices and tight supplies are making negotiations with vendors very difficult, said Stan Martin, purchasing manager for Cianbro, one of Maine’s largest commercial contractors. “It’s a poker game.”

Budgets for most projects a few years ago included an assumption that prices would rise about 6 percent a year between the time a plan was approved and construction. Now, the jetport garage project assumes that prices will rise about 1 percent a month, or 12 percent between anticipated approval and construction.

In the case of the jetport, the difference adds up to millions of dollars. In other instances, projects are being put off by fears of shortages.

The Inn by the Sea in Cape Elizabeth is postponing a $10 million renovation and expansion that had been planned for last October.

“It was a fear of the lack of building materials, more than anything else,” said Rauni Kew, spokeswoman for the hotel.

Engineering News-Record, an industry publication, says prices for most construction supplies rose at a double-digit pace for most of last year. Cement prices were up 13 percent in October 2005 compared to the year before, gypsum products used in wallboard were up 13.7 percent, and copper pipe and tubing was up nearly 25 percent.