Marshalls saw revenue tumble 21% in the first half, in line with trends the paving slab and tile maker highlighted when it raised £34m from a rights issue in May.Revenue for the six months ended 30 June 2009 fell to £166m from £211m in 2008, while underlying daily sales revenue on a like for like basis dropped 19%, the same as for the first four months.As a result of the 2 for 5 rights issue at 65p, Marshalls' borrowings fell to £74m at 30 June from £111m at the end of 2008 and are expected to fall further in the second half."Sales demand remains uncertain with no clear pattern emerging," said the firm. The public sector and commercial market continues to be subdued, but lead indicators suggest a levelling out during the second half of the year. The domestic market has recently performed in line with the group's expectations, with installer order books at the end of June 2009 holding firm at 7.1 weeks.