Mihai Chelmus · Construction Testing, Investigation & Remediation Specialist Email: mihai.chelmus@swantest.co.uk |  Tel: +44 734 228 1981 Construction structural testing, load verification and on-site assessment for buildings, temporary works and safety-critical elements across London.

Structural investigation in London is rarely theoretical. It is undertaken on existing, often occupied buildings, where records are incomplete, construction has evolved over time and decisions carry real safety, cost and regulatory consequences.

For more than a decade, Mihai Chelmus has been directly involved in the delivery and coordination of structural investigation works across London, supporting contractors, consultants, asset owners and dutyholders on refurbishment, change-of-use, remediation and safety-critical projects.

As Operations Manager at Swantest, the specialist testing and investigation arm of Swanton Consulting, Mihai oversees investigation scopes in some of the capital’s most constrained and regulator-scrutinised environments, combining hands-on site experience with senior technical and operational responsibility.

Structural investigations are typically undertaken to establish what is actually present, rather than what drawings or assumptions suggest. In the context of the Building Safety Act, they increasingly form part of the evidence chain supporting structural safety cases, Gateway submissions and long-term asset assurance.

This article sets out the core structural investigation services delivered in London, explaining where they are typically required and why they matter from a compliance, safety and decision-making perspective.

 

Structural Investigation Services Delivered in London and Across the UK
 

Condition and Dimensional Surveys 

 

Condition and dimensional surveys are undertaken to establish the as-built geometry, condition and accessibility of structural elements without intrusive intervention.

On London projects, these surveys are commonly required where:

• Original drawings are missing, incomplete or unreliable
• Buildings have been altered, extended or refurbished over time
• Structural layouts must be verified ahead of design development
• Access constraints prevent immediate intrusive investigation

Surveys typically record member sizes, spans, orientations, visible defects, cracking, corrosion indicators and construction typology. Dimensional data supports load assessment, temporary works design, strengthening schemes and safe sequencing of works.

Borescope Inspection Services 

Borescope inspections allow visual inspection of concealed voids, cavities and inaccessible structural zones through small access points.

Typical applications include:

• Inspection of floor build-ups and voids
• Verification of reinforcement presence and orientation
• Assessment of corrosion, moisture ingress or hidden defects
• Confirmation of structural continuity across interfaces

On refurbishment and heritage projects in London, borescope inspections provide critical intelligence while minimising disruption and damage to existing fabric.

3D Scanning Services 

3D laser scanning is used to generate high-accuracy digital models of existing structures, capturing geometry, levels, tolerances and interfaces.

In London’s dense urban environment, 3D scanning supports:

• Clash detection for refurbishment and retrofit works
• Verification of structural alignment and deformation
• Design coordination where tolerances are critical
• Accurate modelling of complex or irregular structures

Point cloud data provides a reliable basis for design, coordination and risk reduction where traditional survey methods are insufficient.

Concrete GPR Ferro Scanning 

Ground Penetrating Radar (GPR) ferro scanning is used to locate reinforcement, tendons, post-tensioning ducts and embedded services within concrete elements.

GPR surveys are routinely specified where:

• Drilling, coring or fixing works are proposed
• Reinforcement layouts are unknown or uncertain
• Post-tensioned slabs are suspected
• Structural alterations are planned

On London projects, GPR scanning is a critical risk-mitigation tool, reducing the likelihood of accidental damage to reinforcement or services during intrusive works.

Concrete Cover Meter Surveys 

Cover meter surveys measure the depth of concrete cover to reinforcement and help identify bar size and spacing.

These surveys support:

• Durability and service life assessments
• Carbonation and corrosion risk evaluation
• Compliance checks against design or standards
• Targeted intrusive investigation planning

Cover data is often combined with carbonation testing and visual inspection to assess long-term structural performance.

Rebound Hammer (Schmidt Hammer) Testing 

Rebound hammer testing provides an indicative assessment of surface hardness and relative concrete quality.

On London projects, rebound hammer testing is typically used to:

• Identify areas of weak or inconsistent concrete
• Compare relative strength across structural elements
• Support selection of locations for core sampling

While not a substitute for laboratory testing, rebound hammer surveys offer rapid, low-impact insight when used appropriately and interpreted by experienced engineers.

Ultrasonic Thickness Measurement Services

Ultrasonic testing (UT) is used to measure the thickness of steel and metallic elements where access is limited to one face.

Applications include:

• Assessment of corrosion loss in steel members
• Verification of residual thickness in plates and sections
• Inspection of concealed or coated steelwork

UT testing supports condition assessments and remaining life evaluations for existing structures and temporary works systems.

Exploratory and Break-Out Works

Exploratory break-outs are undertaken to physically expose structural elements for direct inspection and verification.

Typical objectives include:

• Confirming reinforcement size, spacing and detailing
• Verifying slab thickness and construction build-ups
• Inspecting interfaces between structural systems
• Assessing workmanship and construction quality

In London, break-outs are carefully planned to minimise disruption while delivering definitive information where non-destructive methods are insufficient.

Concrete Core Sampling & Compressive Strength Testing
 

Concrete core sampling provides direct laboratory-tested evidence of in-situ concrete strength and condition.

Core testing is commonly required where:

• Structural capacity must be verified
• Change of use or increased loading is proposed
• Fire, impact or deterioration has occurred
• Regulatory or insurer evidence is required

Cores are tested in accredited laboratories for compressive strength, density and other relevant parameters, forming a critical component of structural verification.

Carbonation Depth Testing

Carbonation testing measures the depth of carbonation penetration into concrete, which directly affects reinforcement corrosion risk.

On London projects, carbonation testing supports:

• Durability assessments of aging structures
• Corrosion risk evaluation for reinforced concrete
• Remediation and repair strategy development

Results are often correlated with cover depth data to assess remaining protective capacity.

Structural Investigation, Compliance and the Building Safety Regime

Under the current regulatory environment, structural investigations play a critical role in converting assumptions into verifiable evidence, supporting:

• Gateway 2 and Gateway 3 submissions
• Structural safety declarations
• Golden Thread documentation
• Long-term asset confidence

Structural investigation is not about excessive intrusion. It is about targeted, proportionate evidence gathering that allows informed decisions to be made on safety, compliance and cost.

In London’s high-risk, high-scrutiny construction environment, experience-led investigation remains one of the most effective tools for managing structural uncertainty.