“Mundic” concrete (found in Cornwall and Devon) was made with unstable aggregates from old mine waste tips. Some minerals in this waste, mainly sulphides like iron pyrites, can oxidize, decompose and expand to an extent that can disintegrate the concrete and trigger major structural damage. Mundic screening will identify any potentially unstable aggregates and ascertain the stability of the concrete.


Mundic Testing

JGP can provide the full range of “Mundic” testing services, from structural inspections to laboratory-based analysis, all in accordance with the Mundic Guidelines published by the Royal Institute of Chartered Surveyors (RICS).

A Stage One Assessment involves our engineer inspecting the property and taking cored samples from selected walls, which are subjected to a petrographic examination in our laboratory.  The aggregate type is identified as well as the condition of the concrete.  A report is compiled based on both physical evidence from the building inspection and the petrographic assessment. 

Stage Two would be requested if the concrete contains suspect aggregate, which usually involves the microscopic assessment of the concrete and levels of microscopic sulphides.  Again a report is compiled classifying the concrete based on aspects such as aggregate stability and any concrete deterioration. 

Stage Three is for mundic concrete that appears to be stable.  It is an accelerated weathering test designed to assess if any expansion of the concrete would be at a level that would affect structural integrity.

The concrete is classed as follows:

A1: Sound (100% suitable aggregate)

A2: Currently Sound (<30% Group 2 aggregates at Stage 2)

A3: Currently Sound (>30% Group 2 aggregates at Stage 3)

B: Currently Sound (but contains unstable aggregates)

C: Unsound (unstable due to unsuitable aggregates or other non-mundic causes)

Testing Services