Householders’ complaints about builders and gardeners surged by a fifth last year, with more than half relating to substandard service, Citizens Advice has warned.

Almost 60,000 home improvement problems were reported to the advisory service over the past year – a 19% increase on 2017/18.

Some 54% concerned substandard services such as jobs not being completed on time or shoddy workmanship.

Complaints about window and door installations were up 67% to 7,051 cases, with 43% concerning defective goods and 40% about substandard service.

Householders made 4,632 complaints about major renovations, a 33% increase, and 4,797 complaints about fitted kitchens, up 5%.

Citizens Advice received 8,860 complaints about gardening products and services, a 29% increase, and 5,828 relating to roofing and chimneys.

Citizens Advice said the research could not explain why there had been a significant jump in complaints but warned householders to exercise caution when hiring traders to carry out home repairs.

Chief executive Gillian Guy said: “Increasing numbers of people are turning to Citizens Advice for help after bad building or gardening work threatens to leave them out of pocket.

“When you’re looking to get building work done there are a number of important steps you should take. Always get things like quotes and contracts in writing and keep a copy of your communications and receipts, so you can easily compare what you’re paying for with the end result.

“If you’ve had a problem with a contractor, and you’re not sure what to do or where to go, call the Citizens Advice consumer service on 03454 040506.”

Citizens advice advises householders to:

– Find a trading standards approved trader using local websites or the Government’s TrustMark scheme

– Get references or recommendations from trusted people, or ask the trader for examples of work they have carried out in the past. Try to avoid contractors who won’t give references

– Find out if they are a current member of a trade body, which have codes of practice and can help resolve problems if things go wrong

– Get a written quote – this is different to an estimate. A quote is legally binding and the builder cannot change it without good reason

– Get a written contract – this should cover exactly what you are paying for and everything you have agreed on, like timings, payments, who will pay for materials and subcontractors

– Pay in stages rather than upfront. Where possible try to pay by card as this can provide extra safeguards if something goes wrong

– Keep copies of receipts and your written contract as evidence, as well as photos of any problems