And the plumbing and building materials supplier said it expected market conditions would worsen, particularly in North America.
It has already taken action to reduce its cost base, including cutting 3,000 North American jobs.
The company said turnover and trading profits were up in Europe. But it has been badly hit by operations in North America, where trading profit dropped 40 per cent.
Profits were up in the UK, Scandinavia, Switzerland and the Netherlands but down in France, Austria and Italy.
Wolseley CEO Chip Hornsby said: “We have acted decisively and rapidly in response to the challenging market conditions to take cost out of the group and will continue to do so.
“We remain committed to our strategy and are confident that with our size, scale, financial strength and operating efficiencies, we will emerge from this slowdown as a stronger group with an excellent platform for future growth.”
During the period, Wolseley bought 10 bolt-on acquisitions for £170 million. The group’s half year results for the six months ending 31 January are due to be announced on 17 March.