CONDENSATION

THE PROBLEM

Air within buildings will always contain moisture in vapour form. The amount of airborne moisture present at a given time, is expressed as being relative to the maximum possible at prevailing temperature and is referred to as Relative Humidity. The Relative Humidity (R.H.) fluctuates, depending upon temperature, as warm air is capable of retaining more moisture than cold air.

When the temperature of humid air drops, condensation will occur on the coldest surfaces, if the temperature falls below the Dew Point (D.P.), the point at which excessive airborne moisture can no longer be retained. The Dew Point is normally reached on cold surfaces, but in certain situations, the Dew Point can occur within the fabric of porous building materials, where the resultant condensation is known as Interstitial Condensation.

In normal households, we produce considerable amounts of moisture by using baths, showers, cooking, drying of clothes, use of paraffin or portable gas heaters and even breathing. If heating and ventilation provisions are inadequate then condensation is likely to occur.

THE EFFECTS

The effects of condensation should be instantly recognisable to most householders.

BLACK MOULD

Excessive moisture runs down windows particularly in kitchens, bathrooms and bedrooms, often causing decay to glazing bars and window cills, and unsightly black mould forms on inner surfaces of external walls, and also on clothing and footwear stored in built-in wardrobes. Decorations are spoiled and the general quality of life for occupants is reduced.

CONTROL MEASURES

Measures needed to control/eliminate condensation and its effects are many and varied, and listed below are a number of points to be considered:

1. Eliminate all sources of structural damp due to rising or penetrating damp, defects to rainwater or waste pipes, gutters, etc., faulty plumbing, pointing and external rendering.

2. Moisture produced by occupants must be kept to a minimum. For example:

a) Do not allow kettles to boil for longer than is necessary.
b) Keep bathroom and kitchen doors closed when bathing or cooking.
c) Avoid drying clothes indoors or over radiators.
d) Vent tumble dryers directly outside.
e) Avoid use of paraffin or portable gas heaters (which produce more moisture per gallon than fuel consumed).
f) Provide "dry heating" where possible, via gas or electric central heating or electric convector heaters.
g)  Provide adequate ventilation to all occupied rooms, particularly in kitchens bathrooms and bedrooms.  Electric low voltage humidistatically controlled extractors are particularly effective when installed in kitchens and bathrooms, and maintenance free passive dehumidifiers are again very effective when installed in bedrooms and living areas and have added benefit of no running costs and allow no cold draughts from outside.
h)  Avoid sitting large items of furniture against or adjacent to external walls.
i) Insulation within cavity walls and roofs should be considered or insulated dry lining fitted internally.
j) Mould removers and anti-mould treatments are also available which can be very effective in preventing the regrowth of mould on wall surfaces, particularly where the provision of adequate heating and ventilation is difficult.

THE STRAND SOLUTION
Firstly, it is important to establish whether the dampness being experienced is due to condensation exclusively, or other forms of damp, i.e. rising damp, damp penetration or of course a combination of all these problems. We strongly recommend an audit to identify the following:

THE AUDIT

a) Structural damp problems
b) Relative humidity
c) Ambient temperatures
d) Dew point
e) Surface temperatures
f) Types of heating being used
g) Current ventilation provisions
h) Current installation provisions
i) Current property usage

Once these items have been established, the auditor will be able to recommend specific measures to control or eliminate the condensation and damp problems. Details, drawings and reports will be produced, itemising specific recommendations and to illustrate our proposals relating to heating, installation, ventilation, humidity control and anti-mould treatments. What is expected from the householder to minimise the condensation problem will also be indicated, which if acted upon, will form an important part of the cure.

SHOULD YOU REQUIRE FURTHER INFORMATION REGARDING PROBLEMS ASSOCIATED WITH DAMP OR CONDENSATION, OR OUR AUDIT SERVICE PLEASE DO NOT HESITATE TO CONTACT US.

N.B. If you instruct ourselves to re-visit and inspect the property then a charge of £58.75 Inc of Vat must be sent to us in advance. This money will be refunded if the surveyor finds that the problem is unrelated to our previous work.