First, perhaps we should understand what underpinning is. Buildings are generally supported on concrete foundations which transfer the weight of the building into the ground in such a way that the building does not subsequently move.
However, if the condition of the ground changes for whatever reason, then to avoid continuing movement, the weight of the building needs to be transferred, usually downwards, to more competent soils.
The extension of the original foundation is referred to as underpinning.
Stuart Thornhill, Partner at Jonathan Cornes Associates, Chartered Building Surveyors said; “Underpinning can take several forms, but at its simplest, it is the removal of the poor soils and replacement with mass concrete. The extent of such work and the depths to which it goes should be designed by a structural engineer. This work is subject to building regulations and therefore details should be submitted to the local authority.”
He continued “Building Control will undertake inspections during the works, as a consequence there should be a public record of the works that have been undertaken.”
Therefore, underpinning is an indication that a property has had at some point in its past problems with structural movement and remedial measures taken.
It should therefore follow that such a property presents less of a risk of future problems; probably less so than its neighbour that has not been underpinned.
Stuart said “In my opinion the idea of buying an underpinned property should not be discounted as a possible purchase.”
To understand will help in assessing the structure. In my view a survey of its current condition assessing how it has performed since the underpinning is critical.
This along with professional advice will allow an informed judgement to be made. Insurers can have rather closed minds to such issues but by carrying out the above buildings insurance can usually be obtained.
Alternatively, you may seek a continuation of cover from the existing insurers.
If you require advice concerning a property that has been underpinned or may be in need of underpinning, please contact Stuart Thornhill at Jonathan Cornes Associates via www.jcassociates.co.uk