Pye Homes were building a new housing development of 159 units on a site in Long Hanborough, Oxfordshire.
The initial site investigation report had showed a high volume of change potential in the clay throughout the entire site. As this was an Oxfordshire based project and we are familiar with the ground and confident in our local knowledge of the area we were dubious of these findings and dug a small trench in the site to investigate further. The dig revealed an orangey-brown, sand-like clay below the surface. We then recommended further site investigations before the project began and by using comparative samples the site investigators and geologists concluded an old river bed ran through the site.
By distinguishing the soil differences between the river bed and surrounding area we were able to establish that the client could reduce the size and depth of the foundations affected so as not to reach the old riverbed. This ensured the foundations were varied for dwellings across the site, yet adequate and the discovery ultimately saved the client a significant amount of money.
Throughout the project, we had extensive correspondence with the National House Building Confederation (NHBC) to obtain structural warranties for the client. These warranties came with a challenging inspection process made more difficult in this project with the differing housing designs, the number of dwellings proposed for construction and the differing levels of foundations across the site. Each unit or block had to be checked by the NHBC and meant that we needed to provide widespread explanations regarding the reason for the different foundations, that being due to the river bed, to obtain their approval.