Condensation Problems in the Home

Condensation problems in the home - the signs, causes and solutions

Air contains water vapour. The amount of water in the air is dependent on the air temperature or its relative humidity. The warmer the air the more moisture it will contain so more often than not, hot air is relative to humidity.

When air is saturated it will form beads of water on any non absorbent surface that is colder than the saturated air. This is condensation. The lower temperature air is unable to retain moisture so the extra moisture is released thus forming condensation on walls, on panes, in the air and other surfaces. As condensation generally forms on non-absorbent surfaces, the condensation may not be noticed until mould and mildew form. For surfaces that are hidden from view, the material might already be rotting before it is noticed. In a nutshell, condensation forms when hot air meets cold air.

Signs of Condensation

Condensation is different from rising damp thought are similar in some aspects. They are both "wet". Rising damp can cause salt residue on the walls, stained decors and walls, rusting and breakdown of plastering. On the other hand, condensation will present wet curtains or carpets or bathroom tiles and window sills thriving with mould. If the material affected is timber then it is likely that it is decaying and rotting. The rot may not be easily visible as wood decay works its way from the inside out. Check window sills and is likely that corners are wet and stained with water.

Black mould usually appears when there is a high incidence of condensation. Aside from its unattractiveness, black mould presents a danger to the occupant's health as any form of moulds has spores that can affect sensitive people. The spores can be harmful especially to asthmatics. Where does the moisture in your house come from? The daily household activities contribute to the moisture content of the air inside your house. A person can produce about 2 kg of moisture a day, without any form of heating. These are some of the moisture produce in a household where a kilogram of water equals one litre.

  • personal washing/bathing 1.0 kg
  • Breathing while asleep 0.3 kg
  • Breathing while awake 0.85 kg
  • cooking 3 kg
  • washing and drying clothes 5.5 kg
  • heat produced especially from paraffin and gas heaters
  • moisture from damp structural components like walls, flooring and ceiling
  • Causes of Condensation

    The root cause of condensation is poor ventilation. Back when houses have sufficient natural ventilation, condensation was not problem as homes were not air tight. In the late 20th century conservation became a major issue and one of the first moves for an energy efficient home was to fit homes and buildings with good insulation. Natural ventilation was set aside as "real" fireplaces were replaced by central heating; double-glazed windows, fitted carpeting, and cracks in the attic were effectively sealed by highly efficient insulations.

    Homes became airtight which was a great move towards energy conservation. However, the downside was poor air circulation that was an ideal condition for condensation. The change in lifestyle meant the house is unheated and unoccupied a greater part of the day thereby resulting in cold building interior. Heat generating activities are concentrated during short periods in the morning and evening when the interior is still warming up. As hot air collides with cold air, condensation happens.

    Preventing Condensation in the home

    Improving ventilation and heating could prevent and remedy condensation. However, you have to be sure that the problem is condensation and not rising damp. If you are sure that your house is well protected from rising damp, then there are certain changes in lifestyle that you can do to minimize condensation.

  • Ventilate the bathroom to the outside after a bath or shower. Opening a small window will do.
  • Try to dry clothes in a well-ventilated room. Most dryers are stuck in the creepiest area of the basement that has no window for natural ventilation. Relocate your dryer in a room with adequate natural ventilation. If you can't relocate your dryer, make sure you ventilate the room when you use one.
  • When people come in from the outside, hang their wet coats, umbrellas outside to air dry.
  • Add forced ventilation and extraction fans in areas that have high moisture, like the kitchen and bathroom.
  • Keep furniture a few inches from walls so air can circulate at the back.
  • Change the fuel that you use. Switch to electric as it's the driest. Consider solar power for heating the water.
  • Get a dehumidifier.
  • See to it that your pipes are well insulated/
  • If you have a fireplace, make sure it's not sealed with dirt and debris.
  • It is obvious that there are three ways to prevent and treat condensation. The first is the provision of proper heating as dry heat will decrease humidity thereby preventing condensation. Refrain from using kerosene or paraffin as they are the wettest type of fuel.

    The second way is to provide adequate ventilation. Since most homes are not sealed tight to conserve energy, natural ventilation is no longer applicable. However, the placement of ventilation and or extraction fans in strategic areas like bathrooms and kitchens can help in air circulation which could lead to less air moisture. Cooking ranges and clothes dryers should be vented outside.

    When all things fail, get a dehumidifier. The dehumidifier will take out the moisture from the air. The gadget is highly recommended for rooms that have high humidity level. You can also use a digital hygrometer to keep the room's humidity at the ideal 55 to 65%. If you are looking for cold spots you can use an infrared thermometer to locate such areas in your house.

    "I wish everybody affected by condensation problems would read this and familiarise themselves with the causes of condensation, we are landlords with surveying backgrounds and are constantly bombarded with complaints about condensation (usually between late November and early March, the months when the heating is on and all windows and doors are kept closed) I explain the problem of introducing moisture into the building by all the avenues you mentioned and that unless ventilated the moisture will stay in the building, only to be compounded by more moisture the following day by the same lifestyle of cooking, breathing etc. etc. I explained that the open fire and the "loose" fabric of the building offered a constant air change in buildings and even in single glazed properties of days gone by. When I open a window or two upstairs and downstairs and leave connecting doors open ( if condensation is throughout the property) to allow natural air pressure ventilation, I explain this would draw out a lot of the moist air after a relatively short time and then the windows could be closed. The tenants would agree to this and I would leave, I would hang about outside and in less than a minute would see all the windows close, then after a couple of weeks the tenants would phone me back saying "my recommendations had not helped any", suprise suprise. If they read your article it would reinforce what we have tried to explain for years, this stuff should be taught at school, you have it spot on. Regards "