Pyrite, Mica & Mundic Block Testing Across the UK
Certain aggregates and concrete blocks can deteriorate over time because of pyrite, mica or mundic (defective mine-waste aggregates). These defects can cause cracking, expansion and loss of strength, which in turn can affect structural performance, property value and mortgageability.
The Testing Lab PLC (TTL) works with surveyors, engineers, lenders and property owners to provide specialist pyrite, mica and mundic block testing and laboratory analysis across England, Scotland and Wales.
Specialist testing for pyrite, mica and mundic block
We support:
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Residential properties flagged by surveyors or valuers
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Housing portfolios and estate-wide screening programmes
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Commercial and public buildings with suspected defective concrete or blockwork
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Structural engineers who need objective data to support their assessments
Our role is to provide robust laboratory evidence so that professional advisers can make informed decisions on risk, remediation and value.
What are pyrite, mica and mundic block issues?
Pyrite and reactive aggregates
Pyrite (an iron sulphide mineral) in certain aggregates can oxidise in the presence of moisture and oxygen, producing sulphate and causing expansive reactions in sub-base materials and concrete. This can lead to:
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Heave and distortion of floors and slabs
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Cracking of walls, finishes and service runs
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Changes in level and loss of bearing
Mica
Mica-rich aggregates or blocks can have poor long-term durability and strength, particularly where high mica contents affect bond, stiffness or water resistance. Over time this can contribute to:
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Increased cracking and friability
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Loss of cohesion in concrete or blockwork
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Reduced load-bearing capacity
Mundic block
“Mundic” is a term commonly used for concrete blocks made with mine waste or unsuitable aggregates, particularly in some historic constructions. Issues can include:
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Chemical instability and progressive breakdown of the block
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Loss of strength and cohesion
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Increased porosity, damp and corrosion risk
Because these materials deteriorate differently from modern, well-controlled concrete, they often require specialist testing and careful interpretation.
Why pyrite, mica and mundic defects matter
Pyrite, mica and mundic issues can:
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Affect the structural performance of walls, foundations or floors
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Lead to visible cracking, movement and distortion
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Reduce durability and increase maintenance or remediation costs
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Impact property value and mortgageability, as many lenders require evidence that defects have been assessed and, where necessary, remediated
For buyers, sellers, housing providers and lenders, specialist testing provides clarity and confidence where defects are suspected or flagged in surveys.
To discuss your individual requirements, or to arrange pyrite, mica or mundic block testing, please contact our experienced and dedicated team:
Tel: 0800 177 7264
Email: info@thetestinglab.eu
Or please complete our online call back form by clicking on the “Call Me” button, and we’ll respond promptly.
When should you arrange pyrite, mica or mundic testing?
Testing should be considered when:
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A survey, valuation or home report flags suspected pyrite, mica or mundic block
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There is visible cracking, heave or deterioration consistent with defective aggregates or blocks
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Properties fall within areas known historically for mine-waste aggregates or problematic materials
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Lenders, insurers or building control request evidence-based assessment before progressing a mortgage, sale or project
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Engineers need laboratory data to support options appraisal and remediation design
Testing should always be planned alongside a competent structural or building professional, who will advise on sampling locations and safety.
Our pyrite, mica and mundic testing service
TTL provides a laboratory-centred testing service, working in partnership with surveyors, engineers and contractors. Typical steps include:
Typical tests and investigations we support
Depending on the material and concerns, a pyrite, mica or mundic investigation may draw on:
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Petrographic examination
Detailed microscopic analysis of concrete, blocks or aggregates to identify the presence and distribution of pyrite, mica or mine-waste materials and to assess microcracking, deterioration and overall quality. -
Chemical analysis
Testing for relevant chemical indicators, such as sulphate content or other constituents associated with problematic aggregates. -
Physical and mechanical tests
Strength, density, absorption or related tests on blocks or concrete cores, where appropriate and safe to obtain. -
Condition and classification assessments
Where local or lender-specific classification systems exist (for example, grading of mundic blocks), we can generate data to support the appointed professional in assigning a category.
The exact test suite will be agreed with your surveyor or engineer so that it addresses lender and regulatory expectations without unnecessary cost.
How test results are used
Our test results are typically interpreted by chartered surveyors, structural engineers or specialist consultants. Combined with their on-site observations and professional judgement, the data can be used to:
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Confirm or rule out the presence of problematic materials
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Assess the severity and extent of deterioration
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Support decisions on monitoring, repair, partial replacement or full remediation
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Provide evidence to lenders, insurers and buyers on which to base their decisions
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Inform long-term asset management planning for housing providers and estate owners
TTL’s focus is on delivering reliable, traceable laboratory evidence that integrates smoothly into this wider professional assessment.
Who we work with
We provide pyrite, mica and mundic block testing support for:
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Individual homeowners and buyers (usually via their surveyors)
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Housing associations and local authorities
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National and regional housebuilders
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Commercial and public sector estates
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Chartered surveyors, valuers and structural engineering practices
We are comfortable working as either a direct laboratory partner to the client or as part of a wider professional team.
Why choose The Testing Lab PLC for pyrite, mica and mundic block testing?
Specialist materials testing laboratory
Experienced in concrete, aggregates and building materials, alongside geotechnical, asbestos, radon and other property risks.
Clear, lender-friendly reporting
Results presented in a way that surveyors, engineers and lenders can use directly, with key findings clearly highlighted.
Joined-up property risk services
Ability to combine pyrite/mica/mundic testing with asbestos, radon, Legionella and geotechnical services where projects require a broader view.
Independent. Nationwide.
Supporting clients and professional advisers across England, Scotland & Wales from our National Control Centre in Doncaster.
Areas we cover
From our National Control Centre, we receive and test samples from projects throughout:
- Yorkshire & Humberside
- North East & North West
- East Anglia & East Midlands
- London, South East & South West
- West Midlands, Scotland & Wales
Samples can be sent by courier, haulier or coordinated collection, with full chain-of-custody documentation and agreed turnaround times.
Frequently asked questions about pyrite, mica and mundic block testing
Our Accredited Testing Services
Dear The Testing Lab PLC,
Many thanks for your prompt and professional asbestos survey report service, I would not hesitate to recommend your company in this regard.
This must be an absolute record for getting a report back, considering the surveyor arrived around 3pm – very well done!
Thank you for the very quick response for the quote and scheduling the survey. There’s never any fuss, and always straight forward. Thanks again.
Thank you for offering such a prompt turnaround for ACM testing and for your courteous service in doing so – I had a nervous client to placate and knowing the report would be back with them in such a short time was very reassuring to them, and for no more than a basic service from the competition!
Bradley, thank you for your efforts at short notice today, please pass on our gratitude to your surveyor Tim who did your company proud!
Thank you very much for the air sampling results – and please accept our grateful thanks for resolving this issue so quickly and for the promptness of the report.
Your analyst, Lee, was very helpful and his suggestions and advice appreciated.
We would have no hesitation in recommending The Testing Lab and will be in touch soon with regards arrangements for a full asbestos survey for the rest of the site.
TTL have been working directly as my analyst for the last 12 months on a very complex asbestos removal scheme, they have achieved all of their KPI’s without fail and on a number of occasions surpassed their SLA in acting for us on planning issues associated with the demolition in regard to contamination which cannot be removed as part of the normal sequence of operation.
There reports are always issued within timescales and they have policed the reports by the Licensed asbestos contractor faultlessly sometimes in very difficult circumstances.
