Subsidence without high subsidy: New guide aims to stem costly and unnecessary work, writes Roger Trapp

ENGINEERS' growing tendency to recommend 'over-the- top' treatment of subsidence problems for fear of legal action is creating so much concern that work is under way to produce a guide to best practice.

The project is being co- ordinated by the Institution of Structural Engineers, which has just published a similar report on surveys and inspections of buildings.

Andy Lorans, senior technical officer at the institution, said: 'A ridiculous amount of money is being spent shoring up buildings that do not need it.' Often, an engineer would recommend underpinning the whole building when a less drastic - and cheaper - course of action might suffice.

'It's a bit like doctors in America,' he added, referring to surgeons' practice of carrying out defensive treatment to make themselves immune from multi-million-dollar lawsuits. 'We're worried that engineers aren't making enough of a professional judgement.'

The situation results from the rash of subsidence claims on domestic insurance policies in the wake of the recent spate of dry summers. The problem has become so widespread - with insurance companies keeping lists of particularly vulnerable areas - that it has become easy for surveyors or engineers to assume that any structural problems are attributable to subsidence - especially since neither they nor the householder will be paying for the work.

Jonathan Haynes, head of the building surveying section at Nelson Bakewell, the chartered surveyors, said the problem had certainly been overstated. He pointed out that just because a neighbour has had a problem identified as settlement or subsidence, it does not mean that a crack in your house results from the same cause. It could have been there for years and not be a reason for concern.

Even if there is a problem, it may not be down to subsidence. There are a number of other possible causes of slipping foundations, such as collapsed drains or damage from tree roots.

In London and other big cities, many older houses have cracks caused by bomb damage in the Second World War. Although they are mentioned in structural reports, surveyors tend not to worry about them.

Nor is underpinning a fail- safe solution. Since climatic changes are largely responsible for the condition, a period of heavy rain can correct a dry spell with the result that the opposite of shrinkage - heave - occurs. Some engineers have reported this leading to problems even more serious than the original. In dramatic cases, the material pumped into the foundations to support the building can be squeezed out.

However, the weight of claims has led insurance companies to start querying work. Loss adjusters are increasingly challenging claims, while householders are facing higher premiums. The working party set up by the Institution of Structural Engineers to look at the issue is drawing on the views of all those involved. Besides the engineers and surveyors who diagnose the problems and carry out the work, the institution is involving insurers, mortgage lenders and loss adjusters. The Consumers' Association is being invited to comment on the public's behalf.

It has not yet been decided how the report will be marketed, but the organisation is keen to strike a balance between the interests of its first audience - engineering professionals - and ordinary property owners. 'It's not intended to be totally technical,' Mr Lorans said. 'It's designed to be understood by the intelligent layman.

As such, it is likely to follow the approach of the guidance notes on surveys and inspection of buildings, which have been published in the institution's journal, the Structural Engineer.

These are designed to act as an aide-memoire for engineers. The main part is the appendix, according to Mr Lorans. 'It is a list of things that engineers should look for when carrying out an inspection on a house.'

The notes also point out that it is essential that the structural engineer understands the needs of the client and that the client defines the scope of the report being commissioned.

Mr Haynes of Nelson Bakewell welcomed the guide, but he also introduced a further cause of disgruntlement.

'Insurance companies or loss adjusters tend to appoint structural engineers rather than surveyors,' he said, suggesting they could do the work just as well. 'It's a bit of a tug of war.'

(Photograph omitted)