Condensation moisture in the air can come from a variety of sources in your property. In your property normal day to day activities create water vapour which can lead to condensation in the property.
When warm air meets cold air the air is reduced below its saturation point and as a result water vapour turns from a gas into a liquid. This can be visually observed on window sills, tiles etc. This is known as surface condensation.
There are a variety of condensation types including condensation that can occur within the internal fabric of the building.
As you can observe from the diagram above interstitial condensation is result of the temperature inside a building versus outside the building coming into contact and the air inside a building is at a higher temperature than the external air.
This results in higher pressure forcing the warm air through the structure including the moisture from the inside the home. When the air that is warm and moist cools below its dew point, within the fabric of the building, this forms condensation.
This type of condensation can contribute to:
• Structural damage.
• Timber decay.
• Reduce cost of your property.
Conditions for Condensation - The time of year!
When we enter winter this is the season zone where an increase in warm moist air in the home is increased and as it colder outside condensation can arise
Types of homes and condensation
Timber frame buildings:
These homes are at risk of interstitial condensation and may benefit from an impermeable roofing to prevent water vapour coming into contact with the cladding.
Traditionally designed homes:
Homes that have a flat or decked room have been observed to be a target of condensations. Implementing a barrier on the roof membrane can reduce the impact that condensation can have. This prevents the water vapour from permeating the external environment.
Homes that have brick cavities are susceptible to interstitial condensation with moisture within the home coming into contact with the external cold air and reaching the dew point.
The Causes of Condensation
In dwelling houses condensation is related to modern living standards, economic pressure and change in building design.
1.Moist air can be a result of everyday activities including cooking, bathing, washing and drying clothes. Certain areas of the home produce moisture more than others including bathrooms and kitchens where moist, warm air can then spread to cooler parts of the house to condense on cold surfaces.
2.If a home has a great level of ventilation then the risk of condensation decreases. In the past homes were able to produce ventilation more easily due to the limited use of double glazing windows, and open fire places. However in the current world we seal up our properties with an increase in central heating and full-sealed windows.
A level of consistency is required for ventilation to be effective.
Due to our current economic situation this has resulted in individual selectively heating rooms and using paraffin heaters to reduce costs. This can increase the level of moisture and result in an increase in condensation.
Where does it occur?
This can occur on damp surfaces including plaster, wallpaper and has a high level of connotation with condensation.
What does it look like?
Mould growth will appear on any damp surfaces such as plaster, wallpaper and timber and is associated with condensation problems in many buildings. It can be identified by its appearance (unsightly growths of various colours - greens, yellows, pinks, black, grey or white), odour (musty and damp), and fears of health and hygiene considerations (particularly in food processing industries).
There are three principal features common to the broad range of mould fungi:
1.Simple food requirements: able to exist on non-nutrient materials such as plaster and brick which have traces of contaminating organic matter.
2.Produce vast number of spores which allow rapid adaptation to particular environments.
3.Grow The very quickly under suitable conditions.
The main requirement for the development and growth is a source of moisture although food, oxygen and a suitable temperature are also important. It is available water which is critical to mould development and different materials at the same moisture content often have different water availability.
The appearance of mould growth in buildings often suggests poor standards of property maintenance and/or domestic activities encouraging condensation. Prolonged exposure to mould growth will cause disintegration and disruption of certain painted surfaces. Paper and certain fibre building fabrics may also be softened and deteriorate as some mould species are capable of digesting cellulose.
The Cost of Unchecked Condensation
Respiratory and Allergic Health Effects of Dampness, Mould, and Dampness Related Agents: A Review of the Epidemiologic Evidence Mendell et al (2011)
The evidence produced from the above paper proposed that there were positive associations between dampness and mould with multiple allergic and respiratory effects. It was suggested that prevention methods and remediation could reduce health risks.
What is Rising Damp?
Rising damp is a form of dampness that is present in walls as a result of the water underground or next to walls rising through the fabric of the wall. It is a particular problem in older buildings where the damp proof course (DPC) has become damaged or when the ground level around the house has been raised by the addition of a path or driveway.
The Causes of Rising Damp
Rising damp can occur as a result of ground water finding its way into your home through brickwork or stonework. This ground water contains soluble salts, which deposit on the interior and exterior walls of the property. In turn, these salts draw moisture from the atmosphere giving a permanently damp feeling to the wall. Most ground water contains small quantities of salts which are, in most cases, at an acceptable level. The dampness isn’t necessarily caused by rising damp as there maybe another source of water that you are unaware of causing the problem.
What are the Signs of Rising Damp?
There are certain checks that can be made by yourself without the assistance of a damp surveyor. The simple procedure of looking and running your hands around the suspected rising damp areas will allow you to identify a rising damp problem. The typical signs of identifying rising damp include the following:
1.Horizontal brown or discoloured marks to be seen up to 1 meter in height on interior walls. These will be damp to touch and otherwise known as ‘Tide Marks’
2.Plaster will bubble and peel away from the interior walls
3.Wooden beading and skirting boards will become brittle and eventually show the signs of deterioration
4.Mould on walls
5.Walls will feel damp when touched