Construction materials prices increased 0.4 percent in April and 1.5 percent year-over-year, according to the Department of Labor's Producer Price Index. Materials prices have gone up for five consecutive months, the longest streak in more than two years.

Materials prices for construction continued to climb in April, as the Producer Price Index (PPI) for construction inputs added 0.4 percent in April and 1.5 percent year-over-year. Overall, the nation's wholesale goods prices expanded 0.7 percent in April and are up 3.1 percent year over year, according to a May 14 report.

"While some may interpret this increase as the onset of a period associated with significantly higher inflation, it seems more likely that the consistent uptick in prices is at least partially attributable to the colder-than-normal winter, which interrupted the usual flow of construction inputs," said Associated Builders and Contractors chief economist Anirban Basu. "Nationally, construction spending has not been rising in recent months, which implies recent increases in materials prices are not a purely economic phenomenon."

Nonresidential construction material prices were up 0.5 percent for the month, and are 1.4 percent higher than the same time last year. Crude energy materials prices fell 3.3 percent in April, but are still 6.6 percent higher than one year ago. Natural gas prices decreased more than 10 percent for the second consecutive month.

"The nationwide surge in prices is almost entirely attributable to food prices, which increased 2.7 percent in April alone," Basu said. "Any crops that weren't damaged by the harsh winter are now struggling to survive through a drought affecting large portions of the western United States."

Concrete products prices expanded 0.6 percent in April and 3.4 percent on a year-over-year basis, and iron and steel prices increased 1.5 percent for the month and 3.2 percent year-over-year. Steel mill products prices rose 1.1 percent for the month, and are 2.2 percent higher than one year ago, while crude petroleum prices increased 0.6 percent in April and 5.4 percent compared to April 2013.

Five of the 11 key construction inputs did not experience price increases in April, including nonferrous wire and cable prices, which decreased 1.8 percent on a monthly basis and fell 3.8 percent from April 2013. Prices for prepared asphalt, tar roofing, and siding declined 2.2 percent for the month, and are down 4.6 percent on a year-over-year basis. Softwood lumber prices fell 2.5 percent and are 8.3 percent lower than one year ago, and natural gas prices fell 12 percent in April but are 15.1 percent higher than in April 2013.