Spending on U.S. construction projects edged up 0.4 percent in May, while April's figure was revised down significantly — signs that new building is still uneven despite a growing economy.

The Commerce Departments says the uptick in May brought total construction spending to a seasonally adjusted all-time high of $1.31 trillion, 4.5 percent higher than a year ago.

April's figure was revised down to 0.9 percent from what was originally reported as 1.8 percent gain, which would have been the largest increase in 24 years. That came on the heels of 0.9 percent drop in March, the first monthly drop since last July.

Residential projects increased 0.8 percent in May as new single-family home construction rose 0.6 percent and the volatile apartment building sector jumped 1.6 percent.