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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

    Geophysics Provides Site-Wide Ground Profile Information, Devon

    Near-surface geophysics, comprising ground penetrating radar (GPR) and resistivity, was used to identify the presence, geometry and depth of limestone solution features at a proposed residential development site in Torbay. Following a soakaway test investigation, Ruddlesden geotechnical had concerns that the natural solution features within the limestone bedrock could inhibit the use of conventional soakaway drains at this site. Some conventional trial pitting and trenching had been undertaken with excavation plant, revealing a variable and often absent rock-head profile. Due to the variability and need to keep site disturbance to a minimum, geophysics was considered to be the most suitable method of investigation. Ruddlesden geotechnical have a good working relationship with a specialist team of geophysicists, who, under the instruction of Ruddlesden geotechnical, completed the works on this project. Following the geophysical survey and acquisition of the site, further geotechnical investigation was undertaken to confirm the profile (and depths) provided by the geophysics. The geophysics provided greater site coverage and certainty on the ground conditions, which were proven to be variable and potentially problematic.

    21-yannons-geophys-1

  • Recent projects

    Gas Monitoring for Residential Development in Cornwall

    Ruddlesden geotechnical have been undertaking ground gas monitoring to provide data for a ground gas assessmentfor the proposed residential development of land near Newquay, Cornwall. The Phase 1 Preliminary Contamination Assessment and mining risk assessmentidentified that an Elvan Dyke (coarse-grained igneous intrusion) had previously been quarried within the centre of the proposed development site and that the quarry had subsequently been used as a landfill site and infilled with domestic refuse. As part of the contaminated land assessment, ground gas monitoring wells were installed within windowless sample boreholes, to facilitate the long-term ground gas monitoring. Ruddlesden geotechnical use an infra-red gas analyser to monitor levels of carbon dioxide, methane, oxygen, carbon monoxide, hydrogen sulphide and gas flow.

    19-nansledan-gas-1