More than 200 complaints about rogue builders have been made to trading standards officers in the past year, with victims left more than £1 million out of pocket.
Brighton and Hove City Council said that the sums involved in individual complaints to its trading standards team had been as much as £250,000
The council issued a warning to beware of rogue builders and contractors as demand grows for home improvements, roof conversions, extensions and landscaping.
It said: “The number of complaints regarding home improvements received has been escalating to an exceedingly worrying level, with over 200 complaints received during the past year, involving sums ranging from £5,000 to £250,000.
“Nationally, trading standards services estimate that unscrupulous traders have cost homeowners around £3.5 billion every year.
“To attempt to investigate rogue builders and contractors can be very difficult, especially when there are no documents or paperwork provided and consumers have paid by cash.
“Engaging with traders who are not fully qualified, insured and competent may leave consumers with not only devasting financial losses but also leave their homes in an unacceptable and potentially dangerous condition.
“Actual figures relating to reviewed cases show that a simple knock at the door ‘advising’ the homeowner there is a loose tile on their roof, which they say can be fixed for a few pounds, can and does spiral to a new roof – the existing roof being perfectly sound – at costs of £80,000 to £150,000.
“As long as consumers continue to engage with exploitative traders, they will continue trying to scam and defraud their customers.
“As there is no national registration scheme in the UK, anyone can be a general builder.
“It is therefore very important to stay vigilant and follow these simple but important steps.
“Never employ anyone who cold calls at your home and be wary if they can start immediately. If you at any point feel unsure, call the police.
“Make sure you get details of reliable accredited builders from approved trader schemes, for example, the Trading Standards Buy With Confidence scheme.
“Ensure the scheme you use carries out audits and vets the businesses that are signed up to their platforms.
“Always get written proof of what you and your builder have agreed to in the form of a contract, including a time scale for the work to be completed.”
The council said that people should make payments in stages, adding: “Never pay all the money up front. It’s also best to avoid paying in cash or by banker’s draft as you get no financial protection.”
It recommended that any agreement should income a cancellation notice and advised potential customers to check for appropriate insurance.
The council added: “Check with the building control and planning departments regarding building regulations and planning permission as some consumers assume their builder or architect are dealing with this.”
Councillor Leslie Pumm, who chairs the Equalities, Community Safety and Human Rights Committee, said: “There are a lot of very good reputable builders in the city.
“But we are concerned about reports of rogue operators targeting residents including the elderly and vulnerable.
“Such exploitative practices cause unnecessary distress and financial strain on consumers and often cause more issues than they fix.
“We ask everyone to always make sure you are dealing with a reputable builder and get details confirmed in writing before making any payment.
“If you feel like you were a victim of a rogue builder, do not hesitate to contact Citizens Advice and spread the word among your friends and neighbours to ensure it won’t be easy for them to find more business.”
To contact the Citizens Advice Consumer Service for advice or assistance, call 03454 040506 or 0808 223 1133. This information will then be passed on to trading standards.