As more difficult sites are accessed for self-build, we are finding that piled foundations are required more and more. In previous years, this type of work was generally limited to locations in the south of England due to the prevalence of clay soil, but we are now seeing this countrywide. You may think the risk is no worse than digging standard foundations, however from an insurer’s point of view there are a number of considerations to think about:
•Employers’ Liability – employees could be injured if they are working with heavy machinery and in close proximity of lifting operations
Public Liability – there could be damage to neighbouring properties and damage to underground services
•Works – what plant is being used and what is its value? There are risks of theft, tipping, grounding and potentially even falling into watercourses where piling is being done near a river etc.
Before an insurer can underwrite the risk, they would require certain information, such as why piled foundations are required, for example:
•To provide vertical support for a building. This could arise when the construction is taking place on loose, sandy soils or where the ground level has been ‘made up’ by trucking in additional soil – it may not be possible to compact the soil sufficiently. Alternatively, the weight of the building is such that the top layers of ground are not sufficiently stable or strong enough to carry the weight. In such circumstances, piles are used to transfer the weight of the building down to suitable soil e.g. rock.
•To provide lateral support. E.g. to ensure that embankments do not slip; to hold back surrounding soils whilst construction of a basement takes place, for instance.
•To impart stability to soils. This could involve simple compaction of made up ground (see above) or could involve anchor rock faces.
In addition, insurers are looking for the contractor undertaking the self-build to be experienced in piling works, ideally a member of the Piling Federation or to be CHAS members (The Contractors Health and Safety Assessment Scheme). This gives the insurer an indication of their safe working practices while on site.
The number and depth of piles is also something the insurer needs to know. We often find that coastal properties or plots that are based near water can require a large number of piles which will be a factor (as mentioned previously) in any quotation insurers provide.
Similarly, the diameter of the piles will be a consideration. Minipiles, for example, can sometimes be used in difficult or variable ground conditions causing minimal disruption.
You should also ensure that any designs, plans and specifications are drawn up by professionals with professional indemnity insurance in place.