roofsBuying a House

When buying a property it is recommended that your review the potential subsidence risk, and as such understand the implications and actions you can undertake to reduce any potential risk. There are some specific lender requirements as specified in the Council for Mortgage Lender (CML) guidelines which you should be aware of:

  • The Conveyancer must carry out any searches that may be appropriate to the particular property taking into account its locality and other features (including subsidence)
  • The property requires an insurance policy in place that includes ‘subsidence, heave and landslip’
  • There may be a defect which is not covered by the lender’s valuation report and it is recommended that the borrower should not rely on the valuation report to proceed but should obtain more detailed reports on the condition and value of the property


Previous Subsidence?

If the property owner has previously submitted a subsidence claim, or has any knowledge that the property has suffered historically from subsidence (or in the neighbourhood) then this must be disclosed to their conveyancer. A Valuation Surveyor inspecting a property on behalf of a lender also is required to confirm whether they have any knowledge of subsidence affecting the property or neighbouring dwellings.

Where there is previous subsidence the lender may request detailed reports with a view to:

  • Withdraw or not proceed with a mortgage offer
  • Caveat the offer subject to further investigations

In addition to the traditional National House Building Council (NHBC) Guarantees, when all subsidence repairs are completed there may be a Certificate of Structural Adequacy issued by the technical expert acting on behalf of the insurance company. Read more.

This is issued under guidance of the Institution of Structural Engineers and produced by a qualified Surveyor or Engineer to state that the repairs have been undertaken in keeping with the specification of works required.

In addition, if the repair had required Building Regulations (such as underpinning the foundations) then this would have been approved by the Local Council Building Control and this documentation (including completion certificate) should also be available. Please ensure that your conveyancer obtains this information.

Read less.


Home Owner

Find out whether subsidence is a common problem in the immediate area and whether your property is built on clay soil. These two factors alone will be a good starting point for assessing risk of subsidence.

Distribution of shrink-swell soil

Clay soil characteristics, and the degree to which they will shrink or expand, vary greatly not only between regions but on a single site. London clay is generally the most shrinkable soil type but other clay formations and even silty soils can be shrinkable.

The map shows the distribution of the 2 highest hazard levels of clay across England and Wales.

clay distribution in Great Britain

Property Type

The main issue is not the type of property but the depth of foundations and the proximity of trees and drainage system.

Building regulations and legislation has evolved with increasing understanding of subsidence with the main change appearing in the 1976 where ‘the foundations of a building shall be taken to such a depth, or be so constructed, as to safeguard the building against damage by swelling, shrinking or freezing of the subsoil’.

Conservatories are a higher risk as they are usually built on shallow foundations which can move differentially against the deeper foundations of the main building.

Trees and Vegetation

Identify whether the property is within the zone of influence of surrounding trees.


Check that there are no blockages by lifting the manhole and inspecting the drainage (please take care when doing so).

Alternatively we provide a range of subsidence services to help you identify and manage the risk of subsidence.