Rising Dampness
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.
Solution!
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.
To avoid this problem, Gullivers' always recommend that affected walls be stripped of contaminated plaster up to a minimum of 1.2 metres. Our own specialist plasters will then reinstate the plaster incorporating a salt inhibitant, which will keep the salts locked back within the brickwork.
Dampness at low levels may also be caused by high external ground levels bridging the damp-proof course and it is essential that exterior ground levels are kept to 150mm below the line of the damp-proof course. If the paving is a higher level than an acceptable level it will be necessary to cut this away approximately 150mm from the wall and dig out a 150mm deep trench. This trench can then be back-filled with pea shingle which will allow rainwater etc., to drain below the level of the damp-proof course.
