There are dark stains on the outer walls of Dean Carpenter’s new-build home and when it rains, he says, sheets of water cascade down the brickwork.

Since buying his Bellway property in Bedfordshire a year ago, he has found patches of damp or discoloured tiles, accretions of moss and mould growing in the loft space.

Dean is one of many homeowners on two Bellway estates claiming to have endured lengthy battles with leaking roofs – and time is running out on their structural warranties.

Bellway says it strives to resolve issues as quickly as possible.

Dean, 41, paid £375,000 for his home which was built in 2015.

Each morning he wakes up and worries about the roof, he says.

Two roofing companies have told him there are too few rows of tiles, meaning the overlap isn’t sufficient to prevent water ingress.

But Bellway and its insurers, the National House Building Council (NHBC), have rejected Dean’s claims, saying repair work of a poor standard by an independent builder, didn’t comply with regulations and invalidated his warranty.

It said the NHBC inspections had “not identified a defect within the original construction of Mr Carpenter’s property” or any evidence of a leak or water ingress.

Since then, Bellway has blocked Dean’s emails and threatened legal action if he continues posting critical remarks on Facebook.

“I feel totally fobbed off by Bellway,” he says.

“The roof needs replacing, it needs re-battening, re-tiling and re-relaying correctly.”

Eight people on the Willow Green estate shared their concerns about stained walls, mould, or crumbling mortar in the eaves.

One of them, Robert Degavino, 77, says his loft is full of black mould.

“Bellway came out to inspect the property, but as far as they’re concerned it meets building regulations.

“We’re worried because if it’s constantly getting wet, what’s it going to be like in another five, 10 or 20 years?

“They’re lovely designed houses, I just think it’s poor building practice.”

Bellway says staining on render was not unusual after nine years and the NHBC found no sign of water ingress.

At least six homeowners have complained to Bellway or the NHBC about their roofs.

So far, only one claim has been approved, resulting in major remedial work on a property in November.

Robert Altman, 44, says he and his neighbours in Florence Close, a 10-home development built by Bellway in 2017, are in a similar situation.

They say they are the guinea pigs of a new, flat-roofed design, which has resulted in years of damp or mould on the walls of their bedrooms and bathrooms.

In 2023 Bellway admitted some of the roofs were faulty and agreed to improve ventilation and lay new insulation, but the work took nearly two years, and people’s lofts were exposed for months under scaffolding.

“And the worst of it is, they didn’t fix the problem,” Robert says.

“The specialists who came in to certify the work said there were still dangerous levels of moisture in our lofts.

“It’s just misery after misery and we’ve been left in the cold – we’re spending time on this when we have young families, we all have jobs, and if we want to sell our houses, then we’re not going to be able to.”

Some of the residents are now considering legal action.

Georgina Bright, 32, says damp has been pooling on her upstairs ceiling, such that “all the lights have been flickering” and when an extractor fan was removed “loads of water flew out of it”.

She says although Bellway’s contractors tried to clean up the mould, it is growing again all over her loft and on the bathroom walls.

“It gives me PTSD, the whole thing. It’s horrific.

“And I think sometimes, even when Bellway respond, it’s so unhelpful, it makes me feel really crap.”

Bellway “apologised to any homeowner on Florence Close who had been impacted” and said it had worked hard to resolve outstanding issues, adding the roofs were now “fitted as designed to prevent any future concerns” and a mould treatment specialist would reassess the properties in the Spring.

Paula Higgins, chief executive at the Homeowners Alliance, said the level of cover for newbuild homeowners could be “deeply unfair”.

“The structural warranty is very limited in scope so it can be difficult to get problems resolved – it’s frustrating and residents shouldn’t have to become experts because it’s not their fault.

“We’re relying on private companies with shareholders to provide a public good and I don’t think they take full responsibility for the overall build of these homes,” Mrs Higgins said.

• Once a new build home is built, it’s usually covered by a warranty, which lasts up to 10 years and is split into two periods. The NHBC’s is by far the most common
• For the first two years, the builder is obliged to fix any defects or “snags”, such as unsealed windows. Many homeowners hire professionals to spot them
• From years three to 10, the homeowner is usually insured for structural defects, or where damage has been caused because the foundations or the roof say, have not been built to the correct standards
• During this structural warranty period, minor defects are no longer covered. Damp may be covered, but only if it’s found to be the builder’s fault

Source: Homeowners Alliance

Despite market challenges, Bellway fared better than most of the major house builders over the past year, with profits of £381m.

The company is expected to complete 8,500 homes by April and is said to be confident about its prospects for 2025.

In July, the BBC reported on a Bellway estate in Fordham, Cambridgeshire with thousands of ongoing snagging issues, which prompted dozens of other unhappy customers to get in touch.

A Bellway spokesperson said with the NHBC it would “remediate any legitimate build defects identified” in the first ten years.

“As a responsible developer we strive to resolve any issues as effectively as possible.

“A new home is a hand-built product, so defects do occur and often only become apparent once homeowners move in, as was the case at Florence Close.”

An NHBC spokesperson said it was “committed to raising standards in housebuilding by championing high quality homes”.

“We assure homeowners of our dedication to fairness, thorough investigation and our industry-recognised high standards.”