Damp Issues

Damp

Damp proofing in construction is a type of moisture control barrier applied to walls and floors, at low level, to prevent moisture transmission from external sources into a property.

Damp within a property can be hazardous not only to a property’s condition but also to the occupants within.

Damp can be categorised into 3 groups:

Rising damp, mainly occurs due to the lack of damp proof protection to a property which often brings hygroscopic salts to a wall surface. Whilst the presence of hygroscopic salts on a wall does not necessarily prove the presence of rising damp, these salts are commonly brought to the surface of a wall by water from the subsoil and foundations. Therefore, they are a likely indicator of rising damp.

Condensation damp, is caused by the humidity in your home from cooking, bathing, drying and breathing. It typically gets worse in colder weather when humidity is more likely to condense on walls and windows. Lack of air circulation, ventilation and heating can also exacerbate the condensation damp. If this type of damp occurs and is left untreated it will lead to mould forming.

Penetrating damp, which will be most pronounced after a period of rain that has been driven onto a wall surface, an example could be a dislodged or cracked rainwater pipe allowing rainwater to penetrate the outer leaf of a wall soaking into its fabric.

Thermal /cold bridging, the term bridge literally means a conduit to transfer moisture from one point to another, an example could be

Where external ground levels are higher than the built-in damp-proof course level. (i.e the finished internal floor level).

Where a cavity wall has been built, mortar droppings can accumulate within this cavity to provide a path of capillary action which sheds dampness onto the inner wall leaf.

Where inappropriate cavity wall insulation such as urethane foam fill has been used, which has now been discovered can channel moisture.