Rising dampness is caused by moisture rising in the walls by capillary action. If severe, there will be a tell-tale stain line around the wall and wallpaper may be peeling away. Rising dampness may also cause the skirting boards to rot.
Persistent rising dampness will take chlorides, nitrates and other salts from the soil, which are deposited on the face of the plaster as the water evaporates from the surface. Such salts are hygroscopic, with the effect that the face of the plaster has a tendency to be persistently damp, particularly during periods of high humidity of the atmosphere even after the rising dampness has been arrested.
Many older properties can be affected by rising damp due to the lack of an effective damp proof course, this often being slate or bitumen. Existing damp proof courses can also become ‘bridged’ by high external ground levels or can over time break down.
Gullivers use a product called Dryzone to effectively treat rising dampness in buildings. This is a ‘cream’ which is injected into the walls via 12mm holes which are drilled into the mortar. Once the Dryzone is installed, it diffuses before curing to form a water-repellent resin which prevents further dampness rising up the wall.
In conjunction with any chemical damp proof course injection works that may be undertaken, it is always recommended that affected walls be stripped of contaminated plaster up to a minimum height of 1.20m. Our own specialist plasterers will then reinstate the plaster to specification incorporating a salt retardant additive.
In some instances, it may be found that dampness issues within a property are due to defects such as faulty rainwater goods, porous pointing or ‘bridging’ of the existing damp proof course. Often the presence of internal mould, normally associated with condensation, can sometimes be mistaken by householders as rising or penetrating damp.
All of our Surveyors are trained and experienced and will determine the source and extent of dampness and where necessary provide recommendations for treatment.