Rogue builders cost UK homeowners £14.3bn — how to protect your job

More than a quarter of people who hired a tradesperson for home repairs or improvements in the last 18 months ran into a problem, according to FMB, Federation of Master Builders, citing a new Citizens Advice report. Among those who lost money, the median loss was £750, and 11% lost more than £5,000.

What happened

The report, called Built to Fail: How the home repairs market is failing consumers, backs the FMB's long-running campaign for mandatory licensing of builders. According to the FMB, the report also found that using an accredited trader or a larger, brand-name firm made no difference to the odds of a problem occurring — voluntary accreditation schemes aren't protecting consumers any better than hiring a sole trader. The FMB separately puts the cost of rogue and cowboy builders to UK consumers at an estimated £14.3 billion over the last five years.

The findings land as Parliament prepares to debate the issue directly. Mark Garnier MP's Domestic Building Works Consumer Protection Bill, which would introduce mandatory licensing, is due its second reading in February 2027. The FMB's director general argued the current system is "a fragmented, voluntary system that simply isn't fit for purpose" and called on government to act.

What it means for your project budget

None of this changes our cost estimates directly — labour and material prices are what they are regardless of who's licensed to charge them. But it's a useful reminder that on the biggest-ticket jobs, the gap between a fair quote and a costly mistake often comes down to who you hire, not just what you're paying.

That matters most on projects where redoing botched work is expensive and disruptive:

• Loft conversions Loft conversion, where poor structural work or a missed party wall notice can halt a job entirely. A rooflight conversion typically costs around £44,000, rising to £57,400 for a mansard.
• Boiler and heating work New boiler, where gas and electrical work must legally be done by a registered engineer. A straightforward swap runs around £2,800.
• Kitchen and bathroom remodels New kitchen and Bathroom renovation, where plumbing and electrics are routinely done by unqualified fitters to save money, then fail inspection or leak within a year.
• Rendering and external wall insulation Rendering, where a poorly specified or applied system can trap damp in the wall rather than keep it out.

On a typical mid-range kitchen remodel, the difference between a basic job at £4,900 and a premium one at £9,250 is mostly about materials and cabinetry — but a badly fitted job at any tier can mean paying twice: once for the original work, once to put it right.

How we calculate our figures, and why it's worth checking a quote

We build our cost estimates from labour hours multiplied by local trade rates, plus materials, then check them against market prices and real quotes from the trades we track. That's a reasonable basis for budgeting — but it's not a substitute for vetting the person actually doing the work.

A few practical steps cost nothing and reduce the risk the Citizens Advice report describes:

• Ask for proof of registration where it's legally required — Gas Safe for any gas work, a registered electrician or building control notification for notifiable electrical work, and FENSA or CERTASS for replacement windows.
• Get at least two or three written quotes, not just one, and ask what's included — materials, waste removal, making good.
• Check whether the trader belongs to any recognised accreditation scheme, bearing in mind the report's finding that accreditation alone didn't reduce problems — ask for references and photos of recent, similar jobs too.
• Use our quote checker ("is my quote fair" tool) to see whether a number you've been given sits inside the normal range for your region, size and specification before you sign anything.
• Get anything notifiable — gas, notifiable electrical work, structural changes — certified or signed off, and keep the paperwork; it protects you if something goes wrong later and matters when you come to sell.

The bigger picture

Mandatory licensing, if it eventually becomes law following the Bill's second reading, would shift some of this risk-checking off homeowners and onto a registration system. Until then, the practical defence is the one described above: budget using realistic figures, get multiple quotes, check registrations where the law requires them, and use a quote checker before committing. The projects most worth that extra diligence are the ones where mistakes are hardest and most expensive to undo — structural work, heating, gas and anything behind a wall or under a floor.