Construction costs rose 4.2 percent on an annualized basis in Greater Boston, slightly less than the national average, according to a new industry report.

Nationwide, construction costs rose 5.2 percent over the same period from October 2018 to October 2019, consultants Rider Levett Bucknall (RLB) said.

Boston’s annual increase was the second-lowest of 12 large U.S. metros surveyed in the RLB report, exceeding only Los Angeles. But the Boston area still has the fifth highest construction costs out of 12 major U.S. metros surveyed in the RLB report.

RLB’s comparative cost index tracks construction prices including labor, materials, general contractor and subcontractor overhead costs, fees and taxes on construction contracts.

Peter Moglia, co-chief executive at life science developer Alexandria Real Estate Equities, said this week the company is seeing cost escalation in the 5 percent range and remains leery of rising steel and aluminum costs because of increased tariffs. Contractors are anticipating a construction slowdown beginning late this year and continuing into 2022, which is expected to ease cost increases, he said.

“Although the construction industry continues to add jobs, most of the additions have been unskilled laborers increasing the productivity gap, which has led to above-market pay scales for skilled workers, and overtime to staff projects,” Moglia said in a conference call this week to discuss Alexandria’s quarterly earnings. “The projected slowdown would mitigate this.”