The construction spending rate increased 0.2 percent from March to April, marking a third consecutive month of sluggish gains. Despite the modest increases, the spending rate has improved by 8.6 percent year-over-year, exceeding the 5.0 percent increase recorded from 2012 to 2013.

Construction spending totaled $954 billion in April, 0.2 percent above the revised February total and 8.6 percent higher than in April 2013, according to a June 2 report from the Census Bureau. While a third consecutive month of mixed signals from the public and private sectors shows a lack of urgency following a tepid first quarter, the year-over-year growth trend is encouraging.

"Residential, private nonresidential and public construction spending all have areas of strength but also pockets of weakness," Associated General Contractors of America (AGC) chief economist Ken Simonson said in a statement. "While the overall trend remains more positive than last year, growth is likely to be spotty for the foreseeable future."

Private residential construction spending reached a six-year high in April, but only gained 0.1 percent from the March spending level. The latest total, however, exceeded the year-ago level by 17 percent. Single-family construction rose 1.3 percent in April and 14 percent year-over-year, and multi-family spending soared 4.4 percent and 31 percent, respectively. Improvements to existing single- and multifamily structures slumped 2.2 percent for the month but increased 17 percent from a year ago.

Private nonresidential spending dipped 0.1 percent in April, but climbed 5.6 percent over 12 months. Most major categories increased from year-ago levels, but the largest private segment, power construction fell 0.6 percent for the month and 3.9 percent year-over-year. The fastest-growing private build type was office construction, which jumped 3.1 percent in April and 26 percent since April 2013.

Public construction spending rose 0.8 percent for the month and 1.2 percent year-over-year. The largest public segment, highway and street construction, declined 1.1 percent in April but increased 4.9 percent from a year before. The second-biggest category, educational construction, gained 3.0 percent and 4.9 percent, respectively.

"The outlook for the rest of 2014 remains uneven," Simonson said. "Demand for apartments appears to be very strong, but there are several warning signs about homebuilding. Despite dropping last month, power and manufacturing construction should remain the leading private nonresidential categories, with hefty growth for the year as a whole. The rebound in public construction that occurred last month may not be repeated soon."