WASHINGTON(Reuters) - U.S. construction spending increased more than expected in February as a decline in mortgage rates boosted single-family homebuilding, though rising economic uncertainty because of tariffs on imports could slow momentum.

The Commerce Department's Census Bureau said on Tuesday that construction spending jumped 0.7% after a downwardly revised 0.5% decrease in January. Economists polled by Reuters had forecast construction spending rebounding 0.3% after a previously reported 0.2% decline in January.

Construction spending advanced 2.9% year-on-year in February. Spending on private construction projects rose 0.9%. Investment in residential construction shot up 1.3%, with outlays on new single-family projects rebounding 1.0%.

Mortgage rates have eased from lofty levels at the start of the year. Nonetheless, tariffs on imported goods remain a constraint for builders.

President Donald Trump has ordered a new trade investigation that could heap more duties on imported lumber, adding to existing taxes on Canadian softwood lumber, used in construction, furniture and paper production.

Trump has raised tariffs on Chinese goods to 20% and slapped duties on steel and aluminum. According to the National Association of Homebuilders, "builders estimate a typical cost effect from recent tariff actions at $9,200 per home."

Outlays on multi-family housing units were unchanged in February. Investment in private non-residential structures like offices and factories rose 0.4%.

Spending on public construction projects gained 0.2%. State and local government spending increased 0.4%, while outlays on federal government projects declined 1.6%.

(Reporting by Lucia Mutikani; Editing by Andrea Ricci)