Dozens of flood-resistant doors fitted in the wake of Storm Desmond have broken, the BBC has learned.
People hit by the 2015 Cumbria floods were able to claim government grants of up to £5,000 to install new defences.
But more than 60 have said they had faced issues with new doors funded by the grants, including locks snapping.
One fitting firm said it was resolving the problems but another has gone into liquidation. The government said it was "aware of issues".
Keith Jagger used a grant to fit flood doors at his home in Appleby.
"The back door was always very stiff to open and eventually the locking mechanism completely broke," he said.
Steven Sharrard, the director of Crocodile Flood Solutions which fitted the door, said some customers had faced "locking mechanism issues" and he had been resolving problems at his own expense.
Another firm, Adler and Allan, said it was dealing with "concerns" from 64 customers whose flood doors had been fitted by a subcontractor.
One of their customers, Lis Dales in Kendal, said she had to replace her flood door with a regular one after the lock broke.
Adler and Allan has agreed to fit a flood barrier in front of it but the subcontractor that fitted the door, Watergate Flood Solutions, has gone into liquidation.
Ms Dales said: "We're all still struggling with post-traumatic stress disorder and this trauma has just added to all that."
Adler and Allan said it had "taken on responsibility" to sort the problems. Watergate Flood Solutions could not be reached for a comment.
In Cumbria, 3,856 grants totalling £15m were awarded, according to figures provided by district councils.
A government spokesman said a code of practice was being developed to "improve the standard for flood resistance products".