The cost of materials and services used in construction rose faster last year than the price of completed buildings, according to the Associated General Contractors of America.

The construction trade group said in a news release that potential restrictions on the use of imported construction materials threaten to drive up the prices of infrastructure, buildings and new homes and apartments.

From January 2016 to January 2017, there was a 3.1 percent rise in the costs of materials that go into a range of construction projects, including highways and other infrastructure, schools, private buildings, apartments and houses.

Average hourly earnings for all workers in construction climbed 3.2 percent over the same period. Meanwhile, the price index for new nonresidential buildings – what contractors charge for their work – increased 1.4 percent.

Among the major contributors to the rise in construction material costs over the past year were a nearly 20 percent increase in the cost of milled copper and brass and 11.4 percent increase in the cost of steel, and a 3.7 percent increase in prices for lumber and plywood. The cost of diesel fuel surged nearly 35 percent.

Association officials cited three types of proposals that threaten to drive construction costs even higher: an expansion of "Buy America" provisions for construction materials to a wider variety of federally funded infrastructure projects; punitive tariffs on imported steel used in many types of buildings; and limitations on Canadian lumber that is commonly used in residential projects.