Condensation

CONDENSATION – MOULD – AND YOU

Condensation affects many homes in the UK and especially poorly built homes and Period Homes. In our opinion it is the most common “defect” in housing today. Fortunately it is usually at low levels and we have learnt to live with it: we instinctively open windows etc….

However, many of us ignore it at our peril. Many ignore it and therefore gradually become used to it such that we think it normal despite health problems we suffer as a direct consequence.

Condensation cannot usually be prevented but it can be managed provide occupiers understand it and how our own actions can resolve it to acceptable levels.

The following is a revamped article we found at the website of Dundee City council of all places:-

Reducing Condensation

What is condensation?

Condensation occurs when warm, moist air meets a cold surface such as a window, mirror or wall and causes water droplets to form. The risk of condensation depends upon how moist the air is and how cold the surfaces of the rooms are (vapour condenses if the ambient room temperature falls to, or below, its “dew point”).

De-humidifiers can reduce condensation but are usually only a temporary or partial solution; often designed to kickstart the process of other changes that will create the environment you are looking for.

Types of condensation

There are four types of condensation and the worst period for such problems is September to May:-

1. Surface condensation. This is the most familiar type of condensation, taking the form of water on window panes, cold wall surfaces and tiles.

2. Interstitial condensation. This is condensation forming between walls or within the building structure.

3. Reverse condensation. This is also called “Summer condensation”. If rains drenches a wall and strong sunlight then dries it, the heat can actually force water vapour into the wall. When it then meets an insulated surface, it forms condensation at that barrier.

4. Radiation condensation. This is sometimes called “clear night condensation“. If there is a sudden temperature drop at night, it can cause condensation on the underside of roof coverings, for example: often this drips onto the insulation quilting and causes a distinctive mottled effect upon the quilting (and discolouration).

How you ventilate and heat your home will affect the level of condensation. This means that it is your own lifestyle that causes and can reduce condensation and its nasty effects. The choice is yours!

A particularly potent form of problem condensate is termed “interstitial condensation” which forms droplets within a material that can tend to decay/rot/corrode from the inside out and so is difficult to detect and can mask very serious problems.

HINT – if you are buying a home why not take a good look at the HIP and read the EPC (Energy Performance Certificate). A low “rating” (Band) combined with an inappropriate occupier lifestyle can nearly be guaranteed to produce severe condensation and mould conditions: the EPC could be your first clue that something could be wrong!

HINT – When viewing a home try to go first thing in the morning or just after dinner time as these times can coincide with “worst condensate” periods: look for water droplets on cold windows and both high and low corners of rooms, behind free-standing furniture against outside walls……….. The clues are there to be found if you have the courage to look.

What does condensation do?

Condensation can cause unsightly mould that can damage clothing, furniture, wallpaper and you. This mould can dry, sending spores into the air that can cause widespread health/breathing problems for some people but especially the very young and elderly. Mould is usually seen as ‘black spot’ mould but green, yellow and white moulds may also develop depending on the conditions and the particular surface.

Some forms of mould are termed “toxic” – two species – Stachybotrys chartarum and Aspergillus fumigatum – are more dangerous because they produce mycotoxins which can lead to similar but more exaggerated health effects as well as nausea, headaches, rashes and lung infections. The worst such moulds often have a greenish/yellow synthetic look about them.

How to avoid condensation

These four steps will help you reduce the condensation in your home. They amount to a request for you to change the way you live in the building and to be aware that your actions cause the problem:-

1. Produce less moisture by changes in your lifestyle in the building:

Cooking: To reduce the amount of moisture, cover pots and do not leave kettles boiling.
Washing clothes: Put washing outdoors to dry if you can. If you have to dry clothes inside keep the windows open and the door shut. When using a tumble dryer make sure you vent it to the outside (unless it is the self condensing type).
Washing: shut the bathroom door when you bathe/shower so as to not spread vapour.
Bathroom extractor fan: never turn them off because they are noisy – place a sheet of 80grm paper over the vent grill when the system is “on” and if the paper sticks then the fan may be operating well – if the sheet falls then perhaps your fan is not robust enough?
Paraffin and portable gas heaters: These heaters put a lot of moisture into the air – one gallon of gas or paraffin produces about a gallon of water. It is important to keep the window open a little and the door closed when using these heaters. If you have a problem with condensation try to find other means of heating. PROinspect do not recommend use of such heaters.
Due to the amount of moisture produced by these heaters and the damage condensation can cause, PROinspect recommend landlords to not allow tenants to use paraffin and portable gas heaters in their homes.
Sleeping: once awake in the morning immediately open windows to vent vapour and leave open until you leave for work.
Window frames – frames with “trickle-vents” are ideal and should never be closed. The frames themselves must be of the “thermal break” type whereby inner surfaces are not directly in contact with the outside and so cold is not conducted through the frame.

2. Ventilation to remove moisture

Some ventilation is needed to remove moisture as it is being produced. Keep a small window or vent open when there is moisture in the room (also leave trickle-vents open).
More ventilation is required in the kitchen and bathroom when cooking, washing up, bathing and drying clothes. This can be done by opening the windows wider. Better still, use an extractor fan (these come on automatically when the air becomes humid and are cheap to run – there are several humidivent types units that are costly and highly technical but will nearly totally eliminate condensate and mould if located correctly).
Close the kitchen and bathroom doors when these rooms are in use even if your kitchen or bathroom has an extractor fan. Doing this will stop the moisture reaching other rooms, especially bedrooms, which are often colder and more likely to get condensation.
Allow space for air to circulate in and around your furniture. Open doors to ventilate cupboards and wardrobes – filling them with too many things stops air circulating. Where possible, position wardrobes and furniture against internal walls (if against cold outside walls then leave an airspace behind them).

3. Insulation and draughtproofing

Draughtproofing doors and windows and insulating your loft should reduce fuel costs. When draughtproofing:

Do not block permanent vents;
Do not draughtproof rooms where there is condensation or mould;
Do not draughtproof where there is a fuel burning heater (e.g. gas fire) or cooker;
Do not draughtproof windows in the bathroom or kitchen.

4. Heat your home a little more

When the whole house is warmer, condensation is less likely.
During cold spells, a low heat for a long time is better than switching heaters on high for a short period. Where possible, try to heat the whole house. If you have central heating, set it to provide background warmth in all rooms, including unused rooms.
Variations in temperature will soak-up or release (cause condensate) and so when heating is turned off (after bedtime perhaps) the air cools and releases its vapour just at a time when you are breathing vapour all night in one spot – your bedroom. Perhaps you will now see the benefit of opening windows as much as possible and especially in the mornings.