GEO Site & Testing Services Ltd

What GEO Site & Testing Services Ltd does

GEO Site & Testing Services Ltd (GSTL) is a UKAS-accredited geotechnical testing laboratory and on-site testing services provider based in Llanelli, South West Wales. Established in 2011 and acquired by Phenna Group in December 2020, the company operates a single UKAS 2788 accredited laboratory (ISO 17025) and delivers material testing across two service lines: laboratory testing of soils, rock, aggregates, and concrete, and field/in-situ testing including California Bearing Ratio (CBR), plate bearing tests, concrete sampling, coring, drilling, landfill density testing, and lightweight deflectometer testing. Its clients span civil engineering firms, construction contractors, government/public sector bodies (Highways England, Environment Agency flood defense schemes), renewable energy developers (onshore wind farms, nuclear), and domestic self-build customers across the UK and internationally.

The technical stack centers on modern automated testing equipment — 12-20 fully automated effective stress systems for triaxial testing to BS EN 17892, 10-20 automated permeability systems to BS 1377 PT5/6 and Environment Agency standards, and 21 digitally logged consolidation frames — together with a proprietary bespoke online client portal for 24/7 report access, turnaround monitoring, equipment calibration tracking, and staff training management. GSTL operates differentiated commercial features including free nationwide sample collection (own drivers plus courier backup), competitive rates sourced through partner analytical laboratories, and an intuitive online reporting system that allows clients to download test results and certificates at any time.

GSTL runs a professional-services revenue model with quote-based per-project and per-test pricing. It distributes via direct enterprise field sales (website, phone, email), a self-serve client portal for account management, and referral/word-of-mouth channels supported by case studies and LinkedIn presence. As part of Phenna Group's Infrastructure Division, GSTL benefits from access to the wider TICC (testing, inspection, certification and compliance) network across the UK and internationally, while retaining its standalone GSTL brand.

Name

GEO Site & Testing Services Ltd

Legal name

Geo Site and Testing Services Ltd

Website

https://gstl.co.uk

Company type

Private

Founded year

2011

Operating status

Operating

Headcount range

11–50 employees

Short description

GSTL is a UKAS-accredited geotechnical testing laboratory in Llanelli, Wales, providing soil, rock, aggregate, and concrete laboratory and on-site testing services to civil engineering, construction, government, and renewable energy clients across the UK.

Ownership category

akta.pro rank

Product category

Geotechnical Testing Services

NAICS

Testing Laboratories and Services (541380), Testing Laboratories and Services (54138)

SIC

Services-Testing Laboratories (8734)

akta.pro primary industry

Third-Party Certification, Code Compliance & Regulatory Inspection (ASME/API/ISO) (EUAEAHAN)

akta.pro secondary industry

Data Management, LIMS & Compliance Software (ELN, eDMS, reporting automation) (EUANAJAE)

Keywords

• Geotechnical laboratory testing
• Site investigation services
• Soil and rock testing
• Concrete and aggregate testing
• Contamination testing services

Headquarters

HQ city

Llanelli

HQ country

United Kingdom

HQ region

Europe

Offices1 record

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Operations, Supply Chain, Infrastructure, Technology or R&D, Marketing or Sales

Revenue model

1. Laboratory Testing Services: UKAS accredited laboratory testing for soils, rock, aggregates, and concrete. Services include classification testing, earthworks testing, contamination testing, and strength testing. Revenue generated through per-project testing fees based on test types requested.
2. Site/Field Testing Services: On-site in-situ testing services including CBR testing, plate bearing tests, concrete sampling, coring services, drilling services, and lightweight deflectometer testing. Revenue generated through site visit fees and per-test charges.
3. Sample Logistics and Collection: Free sample collection service from client sites, with courier services used for remote locations. Part of the overall service offering.

Go-to-market motion1 record

Distribution channels3 records

Marketing channels4 records

Core offering

GSTL provides UKAS accredited geotechnical laboratory testing and on-site in-situ testing services for soils, rock, aggregates, and concrete. The business operates two interconnected service lines: laboratory testing (classification, earthworks, contamination, strength, consolidation, and effective stress analysis) and site/field services (CBR, plate bearing, lightweight deflectometer, concrete sampling, coring, drilling, and landfill testing). The company supports civil engineering, construction, government, renewable energy, and domestic self-build clients with free sample collection and online report delivery.

Product overview

GEO Site and Testing Services Ltd (GSTL) is a UKAS-accredited geotechnical testing laboratory and site services provider offering a comprehensive portfolio of material testing services for soils, rock, aggregates, and concrete. The company operates two interconnected service lines: Site Services (field/in-situ testing including CBR, plate bearing tests, lightweight deflectometer testing, concrete sampling, coring, drilling, and landfill testing) and Lab Testing (UKAS 2788 accredited laboratory analysis including aggregate testing, concrete testing, contamination testing, soil testing, rock testing, and effective stress soil testing). Additional support services include free sample collection, online reporting portal, and same/next-day result delivery. Services serve civil engineering, construction, government, renewable energy, and domestic projects across the UK and internationally.

Differentiator

Problem solved

Functional benefit

Quantifiable outcome

• Projects stay on budget and on track through accurate, comprehensive, and rapid UKAS 2788 accredited testing services
• +3 more outcomes

Named customers13 records

Segments4 records

Ideal customer profiles4 records

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature4 records

Partnerships

One partnership is on record.

• Phenna GroupcoreOthers · 1 December 2020GSTL was acquired by Phenna Group in December 2020. As part of the global TICC (Testing, Inspection, Certification and Compliance) group, GSTL benefits from access to wider network of technical businesses, resources, and technical capabilities. Phenna Group operates through five divisions: Infrastructure, Built Environment, Industrials, Food & Life Sciences, and Certification & Compliance.

Scale indicators7 records

Recent moves6 records

Expansion highlights5 records

Broad incumbents

• Bureau Veritas UK: Global TICC major with UK operations covering materials and construction-related testing, inspection, and certification. Competes for large infrastructure tenders and offers broader scope (asset integrity, marine, commodities) beyond GSTL's geotechnical focus.
• SGS UK: One of the world's largest TICC providers with UK construction materials testing services. Competes with GSTL on major infrastructure tenders but operates at much greater scale and breadth.
• Element Materials Testing (UK): International testing laboratory group with UK labs serving construction, infrastructure, and industrial clients across mechanical, chemical, and environmental testing. Larger scale, broader portfolio, and overlapping accreditation-driven testing work.

Direct peers

• Structural Soils: UK geotechnical and geoenvironmental investigation contractor offering drilling, sampling, in-situ testing, and laboratory analysis. Operates in the same specialist segment with overlapping services (soil/rock testing, contamination) and customer overlap.
• Geotechnical Engineering Ltd: UK-based geotechnical site investigation and testing firm providing drilling, sampling, and laboratory testing services to civil engineering and construction clients. Directly comparable in scope (site + lab services) and customer base (contractors, consultants, government).
• TerraTek (UK): UK provider of geotechnical and environmental testing services including UKAS-accredited soil and materials testing. Comparable specialist niche with similar geographic and customer focus on construction and infrastructure.
• Ian Farmer Associates: UK geotechnical and geoenvironmental consultancy and testing firm providing site investigation, soils and materials testing. Comparable in offering mix (site + lab) and reliance on construction/infrastructure demand.
• Wentworth House Partnership: UK specialist in geotechnical and environmental site investigation with in-house UKAS-accredited laboratory for soils, aggregates, and contamination analysis. Similar customer focus on civil engineering and construction projects in the UK.
• ESG (Earth Science Group): UK provider of geotechnical, environmental, and materials testing services including UKAS-accredited laboratory and site investigation work. Closely matches GSTL's combined site and lab testing model and UK construction client mix.

Others

• Phenna Group Built Environment Division: Sister division within GSTL's parent Phenna Group, focused on building-related TICC services. Connected as an ecosystem participant sharing infrastructure, accreditations, and cross-sell opportunities within the same corporate parent.

Market position

Strengths4 records

Weaknesses5 records

Competitive moat5 records

Key risks6 records

Key highlights6 records

Customer concentration

• LinkedInlinkedin.com/company/geo-site-testing-services-ltd

Compliance2 records

Revenue estimate

Valuation estimate

Number of profiles

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about GEO Site & Testing Services Ltd