The Irish company owns Buildbase, Plumbase, Jackson and Selco in Britain and Heiton Buckley, Chadwicks and Macnaughton Blair in Ireland.
Group turnover for the six months to 30 June 2011 was €997m, compared to €979m in the first half of 2010.
Turnover in the early months of the year benefitted from more favourable weather conditions than in the same period last year and the rate of growth moderated in the second quarter, the company said.
While UK turnover was up, In Ireland it was down 6%, due to general weakness of the economy there.
Grafton said that trading in key markets was proving slow to recover but its performance had improved significantly from the historically low levels of the recession.
As previously announced, at the start of this month former BSS chief executive Gavin Slark took over as CEO, with executive chairman Michael Chadwick now taking a non-executive role.