More than 2.5 million people have had a dispute with a builder or decorator over the last three years, a survey has revealed.
Householders are advised to get written agreements with builders before work starts
A quarter of those cases saw formal action taken, according to the research by consumer group Which?, with quality of work the most common source of disagreement.
Traders failing to turn up at agreed times, delays over completion, and properties being left untidy were also major causes of complaints.
Which? said the figures showed householders should always have a written agreement in place with builders or decorators in case a dispute breaks out.
The survey revealed quarter of people failed to receive a written quote from their builder or decorator before work began.
As many as 4% were asked to pay the full amount for the job upfront.
Trader disputes left two in five people out of pocket, with a quarter feeling they were owed at least £500, and one in 10 saying they had lost more than £1,000.
And while most managed to resolve their quarrel, 15% had to seek the help of a professional body and 18% were forced to spend more money by taking the trader to court.
Richard Lloyd, Which? executive director, said: "Being left hundreds of pounds out of pocket after a bad experience with a builder can be a huge blow for families already feeling the pinch."
Which? Legal Service suggests householders find builders through personal recommendations and obtain three detailed quotes before traders begin work.