Topps Tiles like-for-likes declined 1.9% in the 13 weeks ended July 2.
Total sales dropped 1.6%.
Topps Tiles said: “We do not expect to see any material change to trading patterns over the final quarter of the financial year. The business will continue to focus on achieving the efficiencies necessary to drive improved gross margins which will help to offset some of the impact of the challenging environment.”
The retailer has 313 stores and “remains confident” it will achieve its year end target of 320.
Singer analyst Mark Photiades said: “Management had indicated back in June that like-for-likes had started to pick up over the latter part of the first 7 weeks of the second half, so this statement is slightly disappointing.
“We continue to maintain a cautious stance given the exposure to the domestic consumer and the link to the UK housing market.
“Topps did well to grow market share over the first half and this has carried on in Q3, but we are wary of potential competitive threats from either expanding specialists or resurgent DIY sheds, given a backlog of old format stores.”