The proposal is made by the Institution of Structural Engineers in a guide to subsidence in low rise buildings, published earlier this month with the aim of establishing a consensus of best practice.
Pointing out that guarantees or warranties from specialists for underpinning work 'are in many instances worth little more than the paper they are written on in the long term', the organisation believes the proposal will result in 'a more meaningful assurance'.
Under the certificate plan there would be a recommended procedure for carrying out subsidence investigations and remedial work, with the expert chosen to carry out the investigation having the option to issue the certificate at the outset if satisfied that no work is needed.
If the experts decide that action needs to be taken they should design a suitable approach and inspect the work at regular intervals before issuing the certificate.
Andy Lorans, secretary to the task force, said the certificate would not provide protection against firms failing, because nothing could do that.
But it was placing responsibility on the expert who looked at the job at the same time as stopping contractors from 'coming along and doing the work willy-nilly'.
If an engineer failed to carry out the design or check properly the homeowner would have a potential case for negligence without losing the right to take legal action against the contractor.
The guide, compiled over two years by a group representing consultants, contractors, lenders, loss adjusters and local authorities, is a response to the rapid rise in subsidence claims. This has in turn led to a great increase in the number of contractors involved.
While most do the work 'very competently' they are relatively small and, in an industry notorious for company failures, 'there is no assurance that even a well-intentioned firm which issues a guarantee will still be in business in 10 years' time, let alone in 25 years', says the guide.
Mr Lorans added: 'It is not totally cast-iron. It is intended to tell homeowners that they are not likely to experience extensive further damage.'
Among the other issues covered in the guide are the development of a code of practice for handling subsidence insurance and an arbitration process for resolving disputes.
It also aims to prove to lenders and insurers that minor cracking does not make buildings worthless and establish a way of spreading technical information.Reuse content