The plunge, compounded by similarly bad news from Travis Perkins-owned Wickes, provided more evidence of how hard the consumer downturn has hit home enhancement specialists.
Focus, founded by chairman Bill Archer, disclosed to investors that like-for-likes plummeted by 11.7 per cent in the 13 weeks to May 1. The decline was worse than Kingfisher-owned B&Q's 7.7 per cent slump in the 13 weeks to April 30.
Focus is the UK's third-biggest DIY retailer, behind B&Q and Homebase. In the year to October 31 last year, it generated sales of£828 million and pro-forma EBITDA of£75.8 million.
There has been speculation that, following last year's£950 million disposal of Wickes to Travis Perkins, Focus itself may be being prepared for a sale.
On Monday, it emerged that Wickes suffered a 4.9 per cent like-for-like slide in its first half.
The Focus and Wickes figures prompted broker pessimism about the outlook for the DIY sector. CSFB cut its forecasts for B&Q and Homebase. However, the broker was optimistic about improvements at B&Q under new management and said: 'We are encouraged that [chief executive] Ian Cheshire is realistic in his assessment of the problems facing B&Q, arising out of short-term demand conditions and longer-term profitability issues at B&Q Warehouse.'
On Tuesday, the latest BRC sales data indicated DIY retailers had benefited from warm weather in June, but broker Numis remained cautious about the outlook for big-ticket sales.