Identifying Dampness in Buildings
Beware of uninformed advice.
Dampness in buildings takes many forms and it is not unusual for so called experts to mistakenly identify any dampness as rising damp. Similarly, there are many situations where these same people specify repairs that will not solve the problems. It is important to be fully informed, and if in doubt, consult an independent Building Consultant.
The main causes of dampness are- rain water penetration through walls, leaking and blocked down pipes, spoutings and balconies, leaking from bathrooms, condensation, lack of sub floor ventilation, lack of a membrane in below ground construction and rising damp. Each item could take a chapter to discuss all the possibilities, but we will try to simplify the diagnosis here.
1-Penetrating- or wind blown rain is most common in older buildings where there is no wall cavity. Dampness appears over a large area as bubbles and blisters often with under lying whitish salt crystals behind. This is not unusual in up to double brick walls exposed to the weather.
2-External water leaks- These are identified by internal bubbling of paintwork that follows a vertical path in the wall. The appearance is usually higher than wide and often has an orange colour. The colour indicates excessive water entering the wall. Inspecting the outside when it is raining heavily is also helpful.
3-Bathroom leaks- Most common are membrane breakages around showers and baths. Immediately behind the wall there is localized dampness often causing excessive damaged, with an orange tint and sometimes mould growth. Another often overlooked area is sealing behind tap fittings, tap spindles should be sealed to the tiles.
4-Condensation- This shows up as dark spots on walls and ceilings. This usually occurs in the coldest room of the building furthest away from the heating source, most often bedrooms. This is essentially a lifestyle problem where air bourne moisture is generated by activities within the property such as washing and drying clothes, cooking and bathing.
5-Sub floor ventilation- Lack of ventilation leads to moist musty air which can become noticeable inside, or in extreme cases, cause a fungal growth beneath the floor which rots the softer floor boards. This is distinct from floor joists and bearers rotting at the ends where they sit on wet brickwork, the floor drops over the years but is still sound. A gap appears between the flooring and skirtings which can allow musty air to enter the room or cause mould to the edge of carpets. Musty smells alone do not indicate structural problems.
6-Below ground dampness- Many buildings built into slopes have garages and rooms where moisture penetrates from built up ground levels, this is often the result of poor design and/or construction. However, when the property was built, these basement rooms were often called up as store rooms, not habitable rooms, and so water proofing was not mandatory. The dampness often appears as a white salting, sometimes with more moisture excessive salting with the orange tint or in extreme cases, water seepage.
