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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

    Residential Redevelopment of Former Garage

    A human health risk assessment at a proposed residential development site in North Devon was undertaken as part of a wider scope of works comprising a Phase 1 and Phase 2 contamination assessment, followed by the production of a remediation strategy and subsequent validation testing. The Phase 1 assessment indicated that the site was a former garage, part of a larger historical coach depot. The Phase 2 contamination investigation, which comprised windowless sample boreholes and contamination laboratory testing, recorded elevated levels of total petroleum hydrocarbons (TPH)and lead within both made ground and underlying natural soils, associated with a remnant underground storage tank (UST), fuel lines and an off-site tank, within the confines of the former coachworks. The contamination risk assessment indicated the recorded levels of contamination to potentially be harmful to human health, given the proposed residential land use. To protect end users, Ruddlesden recommended that all of the tanks and associated fuel lines be remove, and that all proposed garden/ soft-landscaped areas be capped with a minimum thickness of 600mm topsoil and subsoil underlain by a geotextile membrane. All of Ruddlesden’s reports were approved by the local authority’s environmental health officer and the contaminated land planning condition was satisfied.

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  • Recent projects

    Boreholes for Retaining Wall, North Devon

    To aid the design of a large retaining wallat a former glove factory in North Devon, Ruddlesden geotechnical were commissioned to undertake a geotechnical investigation to provide information on the ground conditions. Combined percussive and rotary drilling was undertaken, to obtain sufficient samples of the near surface soils and deeper rock materials, which could not be readily sampled using percussive or rotary methods in isolation. Cost (and time) savings were made by only mobilising one drilling rig, rather than have undertaken separate phases of investigation for the sampling of soils and rock materials. Photograph of the completed project, courtesy of the architect – Woodward Smith.

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