Condensation used to be associated with poor housing and lifestyle


damp causes

condensation on window

For the cure for condensation within your home call Olympic Construction Certified Damp Surveyors today

Condensation used to be associated with poor housing and lifestyle, but not any longer it is now becoming a growing problem within new properties and homes which have been refurbished with energy saving materials such as double glazing, cavity wall insulation and external cladding.

condensation and mouldThese installations and the sealing up of the natural ventilation paths within the property, such has chimneys, sub-floor ventilation and the eves of a property with PVC cladding, combined with the incorrect use of heating due to the high cost of gas and electricity, and attempts to lower the carbon foot print of the property are turning homes into unhealthy living areas.

These actions result in dampness and mould within the property, due to condensation as a result of the high levels of relative humidity within the air which is measured as a percentage, coming into contact with a cool surface which is below dew point temperature.


The diagrams below give a brief explanation of how moisture and temperature are related, and condensation forms on the cooler surfaces which are at or below dew point temperature.

relative humidity

What is considered as an acceptable living environment?

  • The appropriate operational conditions of a building should first be determined by reference to user requirements and then maintained by controlling the internal temperature, relative humidity and air movement. Human comfort conditions lie in the range of 45%rh to 60%rh at 18 ºC to24 ºC.
  • The internal climate of a building should be controlled in order to ensure the health, well-being and comfort of its occupants and the proper functioning of equipment such as boilers, fires and cookers.
  • Air which is contaminated by combustion products, bacteria, mould, smoke, smells, high levels of CO2, excess water vapour and heat should be removed and replaced by fresh air.
  • The temperature and distribution of that incoming fresh air should be considered in order to avoid it being perceived as an unwanted draught.
  • If, at the designed operational temperature, relative humidity is likely to exceed 70% it will be necessary to extract water vapour from the air, this may be achieved by ventilation or by dehumidification, to prevent the growth of mould and the increased propagation of mites which can result in increased side effects which are incorrectly commonly related to dampness.
  • Heating should be used to maintain air and surface temperatures sufficient to prevent problems associated with excessive humidity, to be effective, the heating regime should be matched to the construction and installed ventilation systems. Using the heating system on an on/off method or only on demand will result in the building fabric not maintaining sufficient surface temperature to prevent it from falling below dew point and therefor condensation will form on the surface and within the structure.


How to control and maintain a healthier living environment

Firstly living in a property which is incorrectly or ineffectively ventilated will lead to problems, its like living with your head in a polyethene bag.

You can still ventilate your property effectively and breathe healthy air as well as being energy efficient, it simply means we need to ensure that we ventilate correctly so that the property can breathe.

Positive Input Ventilation (PIV) reduces the issues of condensation by delivering fresh, filtered and clean air into the home, this method dilutes high levels of humidity and harmful household contaminants, creating a healthy all year round living environment free from condensation.

Piv how it works


Supplementary systems which can be installed

The living environment within the property can be further enhanced by the simple installation of an insulated core vent, this is an effective and cost effective way to ventilate your property and work in tandem with the PIV units, by improving the ventilation, the problems will be reduced quickly, cheaply and efficiently.

The central CORE filter, vent allows moisture laden air to escape the property, as the air Pressure on the inside of the building are higher than those on the outside due to the property being heated.

The difference in the conditions within a property will result in a vapour pressure differential being higher so moving the moisture loaded air from inside to outside, which is the driving force to allow vapour dispersion or ventilation. A core vent stops annoying draughts, reduces heat loss and traffic noise with no energy consumption it is perfect for reducing problems with mould and algae growth the performance being greatly enhanced when used in combination with a PIV unit .

piv unit example