Mundic' is a term that covers a range of potential housing problems that occur in the South West resulting mainly from the use of reactive aggregates in concrete.

The 'mundic' problem arises largely from the use of mine wastes as aggregate in concrete and, generally, affects properties that were built prior to 1950. As a result mortgage lenders insist that all concrete block or mass concrete houses constructed before (and sometimes after) this date undergo a Concrete Screening Test to establish whether the property is at risk from accelerated concrete degradation.

The RICS Guidelines provide the accepted method for determining whether a property is, or could be, affected by the 'mundic' problem. Cornwall Consultants Limited, together with Petrolab Limited, provide a one-stop service to the public and to lending institutions. We assisted with the development of the RICS Guidelines and have considerable experience in the assessment of suspect properties.

The Preliminary Screening Assessment consists of taking several 50 mm diameter drill cores from the walls and footings, where accessible, together with samples from the internal walls. These cores are examined in the laboratory using a stereomicroscope. In most cases this stage places the property as either Class A (pass) or Class C (fail).

If there is an element of doubt where the property cannot be classified Class A or Class C, the Guidelines recommend that further work is undertaken on the samples to resolve the position. This involves the samples being cut into a thin section and being examined petrographicallly using a stereomicroscope.This stage of work could lead to the property being allocated as either Class AB or B. Class AB is normally mortgageable and is also used for dense mass concrete footings. Class B is for concrete that is sound at present but carries a risk of deterioration and as such is normally unmortgageable.

The fee for the testing procedure includes taking samples, under the supervision of a surveyor, petrographic examination and reporting. We have examined over 10,000 properties using the above tests of which approximately 80% have been passed as Class A concrete at the Preliminary Screening stage and approximately 5% have gone straight to Class C. The remaining 15% have undergone Stage 2 examinations and many of these have subsequently been re-graded as Class A or AB.

A Concrete Screening Test can normally be scheduled within one week of instruction. A Stage 1 verbal result is then usually available for the client (providing that payment has been received) two working days after the date of sampling.

We can also test for Alkali-Silica reaction, chloride attack and re-inforcement corrosion.