Phase 2 Site Investigation

Solmek Ltd

What is Site Investigation?

Under our feet is an entire world of human, environmental, hydrological and geological history. In the UK we have processes involved that have formed a highly complex and variable record, the purpose of a site investigation is to explore and interpret this record. Depending on the individual requirements of a client, the site investigation may be very short or part of an evolving continuous process of exploration, interpretation, revision and resolution. Using various intrusive methods we produce high quality interpretative reports for our clients comprising both geotechnical and environmental assessments. At Solmek we are here to help you from start to finish throughout your site investigation.

Site investigations can help to ensure no problems occur during the construction process and research has shown that some of the most common problems on land developments could have been avoided if a suitable site investigation has been carried out. Our site investigations are designed to help you understand the condition of the land underneath the surface, ensuring your redevelopment project can progress smoothly and without interruption. Should you be searching for "Site Investigations", "Phase 2 Site Investigation", or something similar, then be sure to contact us today.

Phase 2

Site Investigation Services

Solmek undertake Phase 2 Site Investigations to assess each aspect highlighted by the Phase 1 Desk Study. This generally comprises a variety of exploratory methods such as boreholes and trial pits to sample potentially contaminated material. The Phase 2 Site Investigation is designed and implemented depending on a number of influencing factors such as the proposed end use, sensitivity of the area, ground conditions, size of site and type of contaminants identified by the desk study.

A Phase 2 contamination assessment is a prerequisite for planning permission from statutory authorities such as the local authority, Environment Agency and NHBC. The primary objection of a site investigation is to help you understand the presence of any ground contamination. Should any issues be found with the ground during a site investigation, then we can also provide remediation works and validation reports upon completion as well.

Greenfield & brownfield sites

5 Importances of site investigation

Analysing Risk From Site Investigations

Chemical analysis of soil and water samples for common contaminants is performed to establish the concentration and extent of any contamination present. All samples are sent for analysis to an accredited MCerts laboratory. From the results, a risk assessment using the “source-pathway-receptor” model in conjunction with the current widely accepted CLEA model would then be carried out and the Preliminary Conceptual Model created during the desk study updated to determine the risks to various receptors. The risk assessment may be Qualitative or Quantitative dependent upon the site. Consideration is given to the risks posed to the receptors below:

1. Human

Users of the proposed site after development, infants are most at risk if a residential development is proposed and these are targeted in our assessments. Remedial measures are given to make the site safe for future development.

2. Construction Workers & Area Impact

The health of the workforce during the construction phase of the development is considered in terms of the PPE that they wear and the facilities to be provided on site. Users in the surrounding area are assessed in terms of contamination prior to, during and after the development has taken place.

3. Vegetation

Plants and trees can be affected by contaminated sites. The risks to these receptors are considered and recommendations are given for topsoil and subsoil placement in soft landscaped and garden areas.

4. Controlled Waters

These include risks to water courses, bodies of water (e.g. Lakes or ponds) and aquifers. Water samples are tested along with leachate of the soil to determine the risks posed to these receptors.

5. Services

Concrete can be attacked by moisture and sulphates creating weakness and instability in foundations. We recommend the optimal concrete mix required to mitigate these circumstances. Some contaminants also attack plastic water pipe and we make an assessment of the ground in relation to service fabric upgrades.

Bespoke Solutions

Difficult Ground Site Investigation Services

At Solmek we understand that some ground areas might be difficult to sample, even with intrusive site investigation services and that's why we offer bespoke solutions for difficult to access areas. Whether it be mobilisation of cranes, barge/pontoon water drilling, handheld drilling equipment or something else, we will ensure a detailed site investigation is carried out and report produced. Over the years, we have worked on all types of site investigation projects across the UK.

So if you're looking for someone to handle a difficult site investigation for you, then be sure to get in touch with us today. One of our team is always on hand to assist. All site investigation services and reports are handled by our team of professional site investigation contractors and engineers, giving you peace of mind you're choosing a skilled and professional site investigation company.

Working across the UK

Intrusive Site Investigation Techniques

Cable percussion drilling, or shell and auger drilling, is the most popular method of retrieving soil samples from the ground whilst also undertaking insitu testing. The drilling technique allows the installation of casing inside the borehole to prevent loose soils collapsing into the hole, allowing the borehole to be advanced to depths of up to 100m. The rigs can be adapted to suit access and headroom requirements. Insitu testing is undertaken in the borehole and includes Standard Penetration Testing (SPT), borehole shear vane testing & permeability testing. The cable percussion drilling technique also allows for the retrieval of undisturbed samples used for laboratory geotechnical testing. Following completion of a borehole, ground gas and water monitoring standpipes can be installed. These allow future measurements of ground gases such as carbon dioxide and methane to be taken as well as long term monitoring of fluctuations in groundwater levels.

The small percussive rig is a compact versatile rig which is tracked under its own power into locations with difficult access, some people refer to small percussive drilling as Window Sampling. It is an ideal method of drilling on smaller sites, e.g. gardens, offering minimal disruption. Sampling, insitu testing and installations similar to the cable percussive rig are adopted. Solmek also have dynamic probing equipment which can be fitted in place of the sampling tools. This allows dynamic probing to be alternated with fully sampled boreholes for a comprehensive investigation.

Solmek are required to check for shallow mine workings and can offer a range of rotary drilling techniques to assess the potential hazards to a development from subsidence due to shallow coal mine workings. The main technique to check for the presence of voids due to shallow mine workings is rotary drilling. Solmek can undertake rotary coring to recover rock core samples of various diameters. These can be used to determine rock quality with information often required by piling contractors for deep foundation and tunnelling design. The cores are then logged by experienced engineering geologists in accordance with the relevant British and European standards.

In order to study the structure of shallow strata, machine excavated trial pits can also be carried out under the control and supervision of an experienced engineer. Our engineers have a thorough understanding and knowledge of geology and soil mechanics. Efficient excavation, spoil and reinstatement management ensures that the sites we work on remain hazard free. Hand excavated trial pits can also be carried out where exposures are required to log and detail existing foundations at suspected subsidence problems. Services can also be exposed by this technique.

Within excavated trial pits Solmek can undertake soakaway testing in accordance with BRE 365 Soakaway design. The results can assess a site to determine whether sustainable drainage (SUDS) can be adopted. Solmek can also carry out insitu plate load and CBR (California Bearing Ratio) testing using a wheeled excavator; these tests are normally carried out during the trial pitting investigation.

Solmek undertake coring of floor slabs in order to assess their construction and substrata. This is useful for the purpose of utilising existing rafts for internal construction e.g. mezzanine floors.

Phase 2

Site Investigation Report

Upon completion of our sampling and testing services, we will provide you with a detailed site investigation report. These are designed to be easily understandable, ensuring you know how to correctly proceed with remediation works and validation upon completion. Our team at Solmek will work closely with you from start to finish, to ensure your site investigation report is delivered back to you correctly and you fully understand the information being presented to you. From construction site investigations to marine overwater site investigations and much more, we have you covered.

Intrusive Testing

Methods of Site Investigation

The most appropriate methods of intrusive investigation are determined following completion of a desk study. Understanding the behaviour of the underlying ground is an integral part of any site investigation. It is important that the right combination of drilling, insitu testing, sampling, logging, laboratory testing and analysis are applied within the Phase 2 Intrusive Site Investigation. Solmek uses a number of high quality drilling rigs and plant equipment to produce site investigation data which is tailored to our client’s needs. Following the soil retrieval, our experienced engineers can manage the samples from site and ensure they are transported safely and accurately for extensive ranges of geotechnical and contamination laboratory testing. This ensures we deliver the appropriate data for effective, factual and interpretative reporting.

Service Depth Range (>5m) Depth Range (>10m) Number per day Area Required Cost Reinstatement Costs Gas Installations Sample Types
Cable Percussive Rig Yes Yes Depth Dependent 6m² Mod Low-Mod Yes Undisturbed, disturbed, SPTs
Small Percussive Rig Yes No 5-6 4m² Low Low Yes Disturbed, SPTs
Rotary Rig Yes Yes Depth Dependent 8m² High Mod-High Yes Undisturbed, disturbed, SPTs, rock core
Trial Pits (Mechanical) Yes No 5-10 4m² Low High No Disturbed
Hand Held Machinery Yes No 5-10 2m² Low Low Yes Disturbed
Phase 2 Site Investigation

frequently asked questions

Site investigations are one of the most popular services we carry out for our clients across the UK. Our experts have the skills and knowledge needed to handle any scale site investigation project. Should you have any other questions, please don't hesitate to contact Solmek and one of our team will be happy to assist you.

A site investigation is used to determine the properties of soil and rock and how they might react when disturbed by development or with materials being added to the area. Phase 2 site investigations are carried out on the completion of a phase 1 report, which uses the collation of information from the desk study to impact the works carried out in phase 2.

A site investigation report is completed upon the initial completion of phase 2 works. The report will include collecting information relating to the potential quality and contamination hazards of the soil and subsurface. 

Site investigation is important as it helps you understand the area you are developing better, meaning you can make more informed decisions about the materials to use and the construction process. In addition to this, any necessary remedial works can be carried out before the primary works starts. Without a site investigation report, you could find yourself suffering material interactions and potential contaminants being exposed into the area without the correct treatment.

The cost of a typical site investigation will vary based on whether it's a residential, commercial or industrial project. In addition to this, we also consider whether a site is greenfield or brownfield. We believe in providing cost-effective site investigation solutions.

The objective of a site investigation is to ensure you have the necessary land information and risk assessments in place before any development, demolition or construction work beings. One of the main aims being to test the ground quality and to check for any contaminations.

Why Choose Us For Site Investigations?


Years of Experience


Completed Projects

If you're in need of effective site investigation in the UK, then be sure to contact Solmek to see how we can help you with a detailed site investigation and report.

When it comes to site investigations in the UK, you can count on Solmek to provide a comprehensive service from start to finish. We cover a wide range of site investigations such as marine site investigation, borehole site investigation, brownfield site investigation, environmental site investigation, offshore site investigation and much more. We have a team of dedicated and fully trained site investigation contractors who will ensure all testing and reporting is carried out to the highest standards. For more information, be sure to contact Solmek today.


What Our Clients Say...

"We have used Solmek for a number of years to carry out site investigations on a great number of sites and would have no hesitation recommending them to any Clients for this type of work. Solmek have always been reliable, trust worthy and pro-active dealing with issues as they arise on site in a truly professional manner."

Paul Winship
Partner, Billinghurst George And Partners

"Solmek have undertaken Phase 1 Desk Studies and Phase 2 Site Investigations across a large number of County Durham Housing Group’s (CDHG) sites. Solmek provided a quick and efficient service, they have been proactive in dealing with an queries arising and we look forward to working with them again in the future."

Tom Winter
Development Officer, County Durham Housing Group

Solmek - One of the UK's Leading site investigation companies

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