Dampness in Buildings
The predominant reason that building materials biodegrade is that they are affected by water. It is fundamental to the preservation and maintenance of all buildings that they remain as watertight as their design will allow.
Common Causes of water ingress
Any defect permitting access of moisture into the fabric of a building must be remedied or treated, further entry of water must be prevented, and the area affected by water dried out. In order to identify defects that can lead to water ingress and to identify areas within the building that are at risk of fungal decay, a detailed inspection should be undertaken by a competent specialist. Attention should be given to:
The lists below are intended to be a very simple guide and cannot be exhaustive. If you are concerned that water ingress has taken place it is important to engage the services of a trained and competent specialist who can conduct all the necessary diagnostic investigations.
- Blocked gutters, especially in the hidden valleys of the roof or defective rainwater goods.
- Defective surfacing to valley gutters and flat roofs.
- Missing, broken, displaced or loose tiles or slates.
- Faulty flashing around chimneys.
- Deterioration of mortar in brickwork joints.
- Faulty or missing damp proof course.
- Bridging over the damp proof course by the soil in flower beds, plinths, etc.
- Blocked air-bricks.
- Cracked or broken pipes, both water-pipes and waste pipes.
- Faulty flashing around window frames (throats to sills).
- Continued overflow from cisterns or water tanks.
Ivy or other climbing plants may hide many of the above faults and roots may undermine foundations causing breaks in damp courses. Roots of nearby trees may cause similar damage to foundations and damp-courses.
Look for the evidence of moisture penetration where the outside inspection has identified faults. In addition, a number of potential causes of dampness will not be visible from the outside:
- Solid stone or concrete floors with wooden skirtings and/or covered with timber where the impervious membrane is punctured or of poor quality or where no membrane is fitted.
- Condensation – this may be caused by unlagged steam pipes, especially under floors; b) steam condensate, particularly in wet process factories; c) high atmospheric moisture from the normal bathroom and kitchen usage. This is especially important in uninsulated and/or poorly ventilated buildings and is often the cause of decay.
- Trapping of flood-water in under-floor space and over concrete.
- Plumbing defects and defective toilets, either from fracture of the pan or, more commonly, defects in the plumbing unions.
- Close-fitting linoleum vinyl or laminate flooring installed over unventilated or imperfectly ventilated wooden floors.
Adequate sub-floor ventilation is important and careful attention must be given to clearing blocked air vents or air-holes in sleeper walls. Pockets of dead air favor fungal growth and should be eliminated. Steps must be taken to dry out existing dampness and to prevent further entry of water in addition to the eradication of the fungus and repair of damage caused.