The average cost of household building work is up by almost a fifth (19%) on the last quarter, according to the latest figures.

The average cost of a building job is now £12,634 due to the higher cost of labour and materials, up from £10,626 in July to September this year, Checkatrade’s inaugural UK Home Improvement Index found.

However the increase has not dampened consumer demand, with the number of building jobs up by 1% between quarters one and three, the data, based on more than 10.5 million jobs carried out by tradespeople in the UK, shows.

The average cost of a kitchen fitting has gone up by 12% on the previous quarter – now £7,376 compared with £6,574, while insulation installation costs are up 20% to an average £4,634.

The average cost of a plastering job in the third quarter was up 16% to £2,343 and gardening jobs increased by 10% to £679.

The average “handyman” job – typically of a smaller scale than building work – increased by 25% from to £563.

Checkatrade said it welcomed new Competition and Markets Authority guidelines to protect consumers by raising the bar on vetting by so-called “trusted trader” websites.

Checkatrade’s report found roofers were the least trustworthy trade over the last quarter, with 16% of all roofers who applied to its site having their membership application declined.

Roofers were followed by driveway and patio workers, 15% of whom were turned away from the platform.

Chimney sweeps are the highest-rated on the platform, with an almost perfect average score of 9.99.

Checkatrade chief executive Jambu Palaniappan said: “Prices have risen 6% across all jobs, but this quarter’s stand-out finding is the dramatic increase in the average cost of building work, which has seen a 19% surge in average prices.

“This is significant and reflects the ongoing increases in the cost of labour and materials.

“We also continue to see the issue of rogue tradespeople plaguing the industry, with roofing called out as a particular problem area. Our vetting saw us block applications from 16% of the roofers who attempted to join our platform in Q3, and we have proactively reviewed our own approach to this challenging sector.

“All roofers on Checkatrade are being re-vetted and we require them to provide proof of at least six months’ incorporation and trading history, adding a new layer of reassurance for consumers.”