WASHINGTON (Reuters) - U.S. construction spending increased less than expected in April as gains in private homebuilding were blunted by losses in outlays on nonresidential structures and public projects. The Commerce Department said on Tuesday that construction spending rose 0.2% after surging 1.0% in March. Economists polled by Reuters had forecast construction spending gaining 0.5%. Construction spending, which accounts for about 4% of gross domestic product, jumped 9.8% on a year-on-year basis in April. Spending on private construction projects rose 0.4%, lifted by investment in single-family homebuilding. Demand for housing remains robust, though expensive building materials, especially lumber, are constraining builders’ ability to ramp up construction. The government reported last month a plunge in homebuilding in April, with the number of houses authorized for construction but not yet started increasing to the highest level since 1999. Outlays on residential projects increased 1.0% in April. Spending on private nonresidential construction like gas and oil well drilling dropped 0.5% in April. Business investment in nonresidential structures fell in the first quarter for the sixth straight quarter as a rebound in mining exploration, shafts and wells was offset by a drop in commercial and healthcare buildings. Spending on public construction projects fell 0.6% in April. State and local government outlays slipped 0.2%, while federal government spending declined 6.2%. Reporting By Lucia Mutikani; Editing by Andrea Ricci Our Standards: The Thomson Reuters Trust Principles.