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Mould/Condensation Surveys

JHE offer a service of diagnosing the causes of damp and condensation, which can lead to mould, combining a full diagnostic process with a plan for remedial action, along with a programme to eradicate the mould problem.  Insurers, homeowners, landlords and tenants can all benefit from the comprehensive service offered across the UK.

Mould is classed as a category (1) risk to health, as assessed under the Housing Health and Safety Rating System 2000, which is the same class as asbestos. The Environmental Protection Act (1990) classifies mould as a statutory nuisance that must be treated.

JHE has a proven tried and tested process when considering Damp and Condensation issues in any property –

Risk Assessment

Prior to any survey we will carry out a full risk assessment including an assessment of ACM (Asbestos Containing Materials)


JHE’s experienced technical team will then carry out a survey of the property to identify possible causes of damp penetration and condensation inside the property and recommend remedial action.

Our condensation /damp surveys are carried out by placing a small (15mm diameter) remote electronic internal and external enviromental data recorders in the areas where condensation requires monitoring.

These are totally safe and unintrusive to the occupants.

Over an agreed period time, we collate the data that our loggers provide and using our bespoke computer program to generate clear indicative graphs for our clients of the environment of the property which when analysed will provide a comprehensive report of the days and times that the condensation is formed and its relation to the usage of the property at that time.

Our monitors record when the environment encourages the growth of mould including the date and time specific areas of the property enter into ‘the mould growth’ zone on the survey graphs.



  • Moulds are more prevalent if there is:
  • Lack of air circulation
  • Dampness
  • Darkness

Warm air can retain more water as vapour than cold air, and the proportion of water that is actually present to what could potentially be retained at any given temperature is known as the ‘relative humidity’.

Surface condensation is the result of moisture laden air coming into contact with a suitably cold surface.

Surface condensation is the most common cause of mould growth in the UK.

Requirements for mould growth on a particular surface/material relies on the regular presence of moisture.

However many moulds found in properties do not require surface condensation for their development.

It is also important to note that long term maintenance of high humidity (in excess of 70% relative humidity), without condensation, will also cause moulds to develop in stagnant areas especially on ‘moisture sensitive materials’, such as leather, some clothes and paper etc

There are over 100,000 species of mould worldwide.

Less than 100 are commonly reported in UK properties, the most common being Penicillium and Cladosporium.

Stachybotrys  chartarum (atra), a so called ‘toxic mould’, is uncommon but not rare in the uk.

Which species of mould grows where depends on a number of factors including the humidity and the particular substrate. Also the colour of the mould will depend on the particular species as not all moulds are black.

Primary and secondary colonising moulds only require relative humidity maintained in excess of 75% to develop on certain ‘moisture sensitive materials’.


Simple food requirements

Like wood rotting fungi, they produce vast numbers of spores. They can grow quickly under suitable conditions. Moulds have the same requirement for growth and survival as rots.

They require:

  • Oxygen
  • Suitable temperature
  • Nutrients
  • Moisture (condensation/humidity) This is effectively the only controllable factor.

Some fungi produce toxic substances called mycotoxins, these are secondary metabolites: present in fungal spores (and hyphae)
Moulds produce a large number of volatile organic compounds-this gives the typical ‘mouldy’ odour.

There are 4 species of moulds that are considered to be ‘toxic mould’ (this is not a scientific description): –

  • Stachybotrys chartarum
  • Pencillium
  • Aspergillus
  • Fusarium

FUNGI-Life Cycle

  • Spore
  • Germination
  • Hyphae
  • Mycelium/fruiting
  • Colonisation
  • Sporulation