Wolseley chief executive Charles Banks was upbeat about the first-half results.
He said: "The group's principal operations have continued to outperform in their respective markets and we are confident that this trend will continue in the second half."
But Banks added that economic uncertainty in the USA and continental Europe had dented the results slightly. Changes in the value of foreign currencies affected results, reducing operating profit by £10.7m.
The company said global economic and political problems might affect key markets.
The group announced an increase in the dividend of 12% to 5.6p.