We are about to purchase an empty property and our solicitors have mentioned a past subsidence claim and the possibility of underpinning. We can’t get hold of the previous owners so we’re currently organising for a house survey to take place and would like to know how surveyors spot underpinning. Are there certain things the surveyor looks for and is there a particular survey we should get to ensure this is properly investigated? Thank you.
An interesting question! The short answer is, is that it can be very difficult to tell if a property has been underpinned from a visual inspection, as the underpinning is concealed below ground and therefore can’t always be seen during the course of a typical survey inspection.
Occasionally, there can be tell-tale indications of where underpinning has been carried out, for example the edge of an exposed concrete foundation at ground level, but this is not usually the case. As a surveyor, I would be looking for other indications of movement throughout the building, and whether such movement was dormant and historic, or active and progressive and the nature, pattern and severity of the movement. Possibly the only way you could assess whether a property had been underpinned would be to excavate an investigative trial hole adjacent to a section of the foundation to expose a small section. This would be regarded as invasive and therefore outside the scope of the RICS Homebuyers Survey report and Building Survey service.
If you know for a fact that the property in question has definitely been underpinned, then the specification work for this will almost certainly have been prepared, and the subsequent work supervised by a consulting structural engineer and there should be a certificate from the Structural Engineer confirming that the works have been completed to his / her satisfaction. Without this document, you are taking a risk in purchasing the property, and you would probably need to seek a form of indemnity insurance from the seller concerning this work to partially offset the risk. Without any paperwork or documentary evidence of the work, there are likely to be issues on resale.
With regard to the type of survey you should have, a Building Survey Report would probably be more appropriate than an RICS Homebuyers report, if the property has had structural issues previously to such an extent that underpinning was required.