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Established 2004

Ruddlesden geotechnical

Ruddlesden geotechnical provides ground investigation, geotechnical consultancy and contamination assessment services.

Based in Exeter, but covering the whole of the UK, albeit primarily concentrated in the South West, Ruddlesden geotechnical was formed in 2004.

Ruddlesden geotechnical works on behalf of a wide client base, including local, regional and national housing developers, housing associations, commercial developers, building contractors, structural and civil engineers, architects, building consultants, quantity surveyors, local authorities and private individuals.

Development projects range from single dwellings and extensions to large housing estates, multi-storey flats, offices, industrial units, roads, slopes, schools, hospitals and basements.

The services and projects listed on this web-site provide an indication of those undertaken by Ruddlesden geotechnical, but others are carried out. If your requirement is not readily identifiable on this web-site, please contact us as we may still be able to help you.

  • AGS
  • Constructionline
  • CSCS
  • SMAS
  • ECFC trust

Latest news

Recent projects

  • Latest news

    25 Mar 2026

    BRE 365 Soakaway Testing

    Simon Ruddlesden was pleased to present at the AGS Annual Conference, to talk about BRE 365 soakaway testing, asking the question, though not necessarily providing the answer: Should we be carrying out BRE 365 soakaway testing in geologies where previous testing has shown soakaway/ infiltration drainage to be unsuitable? The BRE 365 soakaway test is widely accepted and requested as the field test that is to be carried out to assess the suitability of the ground for soakaway/ infiltration drainage. However, the test is not without danger, mainly due to working at height risks, and it is relatively wasteful of resources, including fuel and water. If previous testing results consistently and convincingly show that certain geologies are unsuitable for soakaway/ infiltration drainage, should a relatively unsafe and not particularly sustainable test be carried out? Using data from over 5,000 tests on more than 1,200 sites investigated by Ruddlesden geotechnical over the last 20 years, mainly in the South West, there is a clear and understandable correlation between unsuccessful tests and the underlying geology, where the underlying geology comprises predominantly lower permeability mudstones and clays, notably the Mercia Mudstone Group, Lias Group and Oxford Clay Formation, although there are a number of anomalies, which can usually be explained by a closer inspection of the local geology, including superficial deposits. More data and research will be required if regulators and designers are to accept that no testing is required in certain geologies. The presentation sparked an interesting discussion afterwards, and it is hoped that it will have inspired others to share their data and/ or offer technical support, to ultimately produce a map that provides confidence to regulators and designers that BRE 365 testing is not required in certain geologies. Please contact us directly if you would like to discuss this further.

    BRE 365 Soakaway Testing
    BRE 365 Soakaway Testing

  • Recent projects

    Close Liaison with Local Authority and NHBC Saves Time and Money

    Ruddlesden geotechnical often liaise with the local authority’s environmental health officer (EHO) and, in some instances, the petroleum officer to gain additional background information about a site. The local authority often have additional information or insight as a result of previous developments within the same area. Ruddlesden geotechnical held favourable discussions with both the EHO and warranty provider (NHBC) regarding the risk of ground gases (carbon dioxide and methane) to a proposed residential development site in Shrewsbury, Shropshire. Initially, the warranty provider felt that in-situ ground gas monitoring was required to ascertain the risk of gases migrating from a nearby landfill site to beneath the site. However, following joint discussions with the EHO, it transpired that historical ground gas monitoring, both on and off the landfill, had shown that the landfill had a relatively low ground gas generation potential and so was unlikely to significantly affect the site. It was agreed that in lieu of in-situ monitoring, nominal ground gas protective measures, akin to full radon protective measures (a gas proof membrane and subfloor ventilation), could be adopted. On this occasion, this pragmatic approach saved the developer significant time and money.

  • Recent projects

    Deep Bore Soakaways, Devon

    Deep-bore soakaway drains were recommended by Ruddlesden geotechnical following observations made during conventional soakaway testing in accordance with BRE DG 365 at a proposed residential development site in Torbay. Previous geotechnical investigation and near-surface geophysics, undertaken as part of a solution feature investigation, had indicated that the use of conventional shallow soakaway drains could lead to the loss of near surface soils through underlying cavernous limestone, potentially leading to a heightened long term subsidence risk of the ground. It was considered that the careful use of deep bore soakaways could mitigate this risk, by transferring surface water into competent limestone at depth, beneath the weathered zone where concentrated flows could trigger subsidence of the ground. The installation of the deep bore soakaways was supervised by Ruddlesden geotechnical, who also carried out in-situ constant head permeability testing post-installation, to confirm the performance of the soakaway drains and the design parameters.

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