DAMPNESS IN BUILDINGS - GENERAL INFORMATION

1. Generally, the coldest part of a property is at the lower ground floor level; warm air rises. Rooms that have original solid floors have no thermal value, as they were not constructed with insulation or a damp proof membrane. Such large cold surfaces shall give rise to heat loss and problems of condensation. Equally, moisture from the ground can rise up. Covering original solid floors with a coating of bitumen will provide a damp barrier however damp can still rise up and around the perimeter edges of the rooms. It is essential that all wall plaster is not in contact with original solid floors. Taking off a section of skirting and hacking off the plaster above the floor leaving exposed brick and reapplying the skirting will help to prevent moisture bridging between the floor and wall through the plaster.
2. Properties left vacant for long periods of time shall lead to plaster becoming addled/perished and wood rotting fungal attack to timbers. During long vacations one should ensure that a de-humidifier is left running at all times.
3. The warmer the atmosphere the more moisture the atmosphere is able to contain. So when heating is then reduced, condensation can readily take place. Dew point also occurs inside a property which is when the temperature inside drops at a point at which air borne moisture turns into globules of water. Keeping a constant moderate temperature within the house and the using of a de-humidifier shall help to reduce condensation.
4. Having your home HOT shall give you a greenhouse effect that shall create air borne moisture and similarly having the house cool shall also give rise to problems of condensation.
5. Achieving the right combination of heating, ventilation and extraction is important to controlling condensation problems.
6. Single glazed windows will be seen to suffer more readily from condensation than double glazed units. If one has this problem initially, that changing to double glazed units one shall see a reduction of condensation however you must realise that you have simply moved the problem to a different position in the room. You have not solved the problem or eliminated problems of condensation! This is only achieved by extraction, ventilation and temperature control.
7. Properties built with walls of solid construction have a low thermal value and as such shall suffer from problems of condensation and an amount of penetrating dampness due to the porosity of the brick. Solid constructed walls can be insulated internally to increase the thermal value of the property although this can be quite expensive. The applying of a silicone treatment to the external brickwork to prevent penetrating dampness is effective. It coats the exposed brickwork with a waterproof repellent.
8. Any wall that are dry lined, that have a timber cladding or panelling applied or are of a tile finish could be concealing defects of problems such as penetrating dampness that can lead to timber defects as such closed conditions can encourage timber decay such as wet or dry rot to take place to such concealed and hidden timbers.
9. Cavity air vents were commonly installed to elevations of properties during the 1900's as it was felt that cavities and rooms should be vented. Today, modern buildings do not use such venting systems. We have realised that venting cavities not only leads to cavity wall tie failure due to interstitial condensation forming on the metal ties but also, because they allow uncontrolled cold air to enter a room which leads to condensation problems.
10. The only vents required to a building are for venting a sub-floor, for a gas appliance or for providing ventilation to a roof void. Over and above this, all cavity vents should be sealed up.