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dropletsDespite the fact that condensation is one of the most commonly occurring forms of unwanted dampness in residential properties in the UK it is surprising that there is a general lack of understanding amongst the public and even professionals about its causes, capabilities and how to reduce it.

If you have a condensation problem we suggest that you read Informative Article 1 on this site which is a detailed explanation about condensation written by Graham Coleman, one of the country's leading experts. You should also read the short articles in condensation explained which are written in in an easy to follow format that it is hoped will help you understand why condensation forms, how to reduce it and how water vapour is distributed.

To help with your understanding of condensation it is perhaps better to start with the meanings of words commonly used when condensation is being discussed.



Condensation is the change in matter of a substance to a denser phase, such as a gas (or vapour) to a liquid.



Liquid which has been condensed from a vapour is called condensate. Water is the liquid condensed from water vapour that forms on cool surfaces.


Dew Point (temperature)

Dew point is the temperature at which water vapour reverts from its gas state to a liquid. Sometimes referred to as dew point temperature.

Or for the purists:

The dew point of a given parcel of air is the temperature to which the parcel must be cooled at constant barometric pressure, for the water vapour component to condense into water.



Relative Humidity

Relative humidity is the term used to describe the amount of water vapour in the atmosphere at a given temperature expressed as a percentage of the maximum possible at that temperature.

Or for the purists:

Relative humidity is defined as the ratio of the partial pressure of water vapour in a gaseous mixture of air and water to the saturated vapour pressure of water at a given temperature. Relative humidity is expressed as a percentage.



Vapour is the gaseous state of matter that is a solid or liquid at normal room temperature.


Vapour Pressure

The balance between condensation and evaporation gives the quantity called vapour partial pressure which is abbreviated to Vapour Pressure. Vapour Pressure is an indication of a liquid's evaporation rate. It relates to the tendency of molecules and atoms to escape from a liquid or a solid. A substance with a high vapour pressure at normal temperatures is often referred to as volatile - an example being petrol. The higher the vapour pressure of a material at a given temperature, the lower its boiling point.


Water Vapour

Water vapour is the gas phase of water.

Contact Peter: Email - info@dampdecay.co.uk - Telephone: 015242 71794