MUNDIC TESTING GUIDE (in plain English)

So your mortgage application has suddenly ground to halt at a crucial time because the lender has asked for something called a ‘Mundic Test’…?

Here we explain what this means; how much it costs and how to order one, all in plain English. If you have any more questions please contact us using the form below or give us a call on 01209 313511.

So, what do you want to know first…?

What is 'Mundic?'

sulphidessThe word ‘Mundic’ is a Cornish mining term for the sulphide mineral pyrite, which is found in many of Cornwall and Devon’s rocks.

Nowadays, the term Mundic is synonymous with several forms of concrete degradation in the region and the testing process used to assess it.

What does 'Mundic' have to do with concrete?
Progressive degredationConcrete has three ingredients:

  • Aggregate – bits of rock that need sticking together
  • Cement – the glue that sticks the aggregate together
  • Water – to help it all mix together and set

Waste rock from metal mining was used as a free aggregate in the past. The mine waste contains Mundic, which when exposed to moisture, attacks the cement (the glue).

This causes the concrete to weaken; crumble and fall apart in the worst cases.

Why do I need a 'Mundic' test?
Probably because your mortgage lender has insisted on it and wants to check that the property is not affected.

   Is the property in Cornwall or West Devon?


   Has any part of the property (including any extensions) been built between 1900 and 1960?


   Does any part of the property contain concrete block, or mass concrete? (Stone and brick is not affected by mundic.)

 or alternatively:

   Has a lender or other body requested a test to confirm the construction of the property? (Irrespective of construction and dates.)

…then you’ll need to get a test.

How does the 'Mundic' test work?
Our Mundic surveyor tells the driller from where to take samples so as to best represent the house construction.Mundic testing

Our driller will collect samples of the concrete in the house walls and footings using a drill. [samples are 50-75mm wide cores]

The samples are analysed at a specialist local laboratory for mundic.

Our surveyor writes a report clearly stating the result.

Has this house been tested before?
samplesYou can call us on 01209 313511 or email us at to ask.

We will happily tell you if this house has been tested before by us, but we cannot tell you the result. (This is confidential to the original client).

Alternatively you can click on this link to use the Mundic Property Search Tool offered by our friends at Petrolab.

Does the Mundic report have to be in my name or can I use an old one?
Your mortgage lender will always want to see your name and sometimes theirs, on the Mundic report. If it doesn’t have your name on it, then you can’t legally rely on it even if the result is correct.

Reports can be re-assigned (transferred) to a new client by the original attending surveyor, but many surveyors who previously provided this service have ceased trading or no longer offer the service and therefore re-assignment is not possible.

Changes to the rules governing Mundic testing mean that many reports older than 6-10 years are not re-assigned.

How long does a Mundic test report last?
There is no fixed rule on this (see the answer to the previous question). If you have sight of an old report then give us a call to discuss it on 01209 313511.

A new Mundic test with us will last longer than those historic ones. Cornwall Consultants Ltd no longer relies on external independent surveyors but undertakes this work in house, meaning that we retain the power to transfer reports in the future.

OK ...How much?

The standard Stage 1 Mundic Test will cost from £415 (excluding vat).

This applies to a typical residential house in mid or west Cornwall.

Higher fees apply to larger properties; commercial sites and those in east Cornwall and west Devon.

I need to get on with it...How long will it take?

We are the fastest provider of Mundic Testing services around.

  • Lab2We will arrange the sampling to be undertaken within about 8 days (often quicker).
  • The laboratory analysis takes about 1 or 2 days (we can often give verbal results at this time)
  • Our final surveyors’ report is completed as soon as the results are received.

So, if you order today you would typically have the final report within 2 weeks. If this isn’t quick enough then let us know and we’ll do everything we can to meet your deadline. Fill out the form below to get things moving…  

Who makes the rules?

Guidelines on test requirements are provided by The Royal Institution of Chartered Surveyors (RICS). The third edition of these guidance notes came into effect in January 2016. Cornwall Consultants Limited have a dedicated and RICS qualified chartered surveyor who is with many years of mundic assessment experience.

We provide a fast and hassle-free service, coordinating the sampling, expert supervision and laboratory analysis. The findings are detailed in a combined report designed to meet the requirements of all major mortgage lenders and comply with the RICS Mundic Guidance Note 3rd Edition.

What does Class C mean?
The result of the Stage 1 Mundic screening test classifies the concrete from each sample in to one of the following:

  • Class A1
  • Class C1 or C2
  • Unclassified

Stage 2 analysis can further classify the samples in to:

  • Class A2
  • Class B

Stage 3 testing can give the classification:

  • Class A3
  • Class B

Anything with ‘A’ in it is good news. Although the others might be a problem, several of these can be rectified by removal of affected concrete. SEE OUR CLASSIFICATIONS GUIDE (below right) FOR MORE INFO…

I also need a Homebuyer's Survey - can you help?
We don’t undertake Homebuyer’s; Valuation or Building Surveys directly, however we can recommend the following professionals to assist:

R H Benwell & Associates

M Mullaly Chartered Surveyor

To initiate a Mundic Test or just find out more please fill out the form below and we’ll contact you shortly. If you’ve already had a test and want to know what the result means, just click the tabs on the right……>>>>>>>>>>>

  • We will email you with a quotation as soon as possible after you submit this enquiry. Sometimes, we might contact you for more information before confirming the final price.
  • Please add your phone number if prefer to receive a phone call about your enquiry.
    Knowing the size of the building helps us to provide the lowest appropriate price.
    All extensions and outbuildings will need to be considered irrespective of building material unless evidence of 'safe' age can be provided.
  • Mortgage lenders typically wish to be included on the report. Please include the name of the bank/building society if there is one.


Class A1 means that no mundic has been found in the concrete; it is not affected now, nor can it become affected in the future*.

This is determined by a normal STAGE1 screening test, the most common test undertaken and always the starting point. About 80% of Stage1 tests achieve Class A1.

*Although ClassA1 samples cannot change, samples are only taken at certain points. Mundic can occur in a property Classed A1, if a mixture of concrete was used and no sample of the affected area was taken. It is the role of the surveyor to design a representative sampling regime in accordance with the RICS guidance.


(needs further testing to determine mortgageability)

‘Unclassified’ means that some mundic has been identified in the concrete but we can’t tell how much from the Stage 1 screening test.

This is determined by Stage 1 testing, but no specific classification can be assigned without doing more detailed testing by one of the Stage 2 methods. Many ‘unclassified’ concrete samples go on to pass at Stage 2 testing by achieving a Class A2 classification. Some will pass at Stage 3 to achieve Class A3. Some will fail and achieve Class B.


Class C1 means that the concrete contains mundic and this is already attacking the cement, weakening the concrete. These samples are considered ‘unsound’ meaning they are fractured, broken, voided, or crumbly.

This is determined from either Stage 1 or 2 testing. If found to be localised within a building, Class C1 concrete can sometimes be physically removed and replaced.


Class C2 means that the concrete does not actually contain large proportions of mundic, but it is weak, broken or crumbly (unsound) for another reason.

Class C2 is determined by Stage 1 or Stage 2 testing. If found to be localised within a building, Class C2 concrete can be due to a range of building issues (other concrete quality problems); water infiltration or attack from flue gasses in chimneys are typical. Class C2 concrete can sometimes be physically removed and replaced.


Class A2 means that the concrete contains some mundic but not a large proportion and there is no sign of degradation.

This is defined by a STAGE 2 test (either petrographic; dry density or chemical). Stage 2 tests are undertaken if samples have been defined as UNCLASSIFIED from Stage 1.


Class B means that mundic has been found to make up more than 30% of the concrete. No assurances for the future of the concrete can be provided at this stage even if it appears sound.

This is determined by a Stage 2 test. Whilst it is possible in some cases to undertake Stage 3 testing to try to achieve Class A3, this is not always appropriate. If found to be localised within a building, Class B concrete can sometimes be physically removed and replaced.


Class A3 means that the concrete contains a greater proportion of mundic than Class A2 but it has been shown that it is unlikely to suffer adverse effects in the future.

This is determined by Stage 3 testing, which involves exposing samples to accelerated weathering to see how the concrete will hold up in the future. Stage 3 testing is an option for samples found to be Class B, but Stage 3 testing is very expensive and in some cases can take up to a year to complete. It is not appropriate in all circumstances.

*Clients should check the acceptability to lenders of the possible outcomes before instructing Stage 3 testing.

Please click here for further information on Mundic.

Recently mortgage lenders are becoming increasingly cautious of this issue and tests are often instructed in order to prove the type of construction materials rather than merely to assess concrete for mundic degradation. Similarly lenders may now require more extensive testing of buildings containing leasehold flats and apartments than before and insist on repeating formerly ‘clear’ tests in circumstances where the original surveyor is not available to re-assign the report. Advice should be sought from your mortgage lender on their specific requirements to enable us to tailor the work to suit. Our staff are experienced in all aspects of this work and will be happy to guide you through this procedure.