What is Lateral/Penetrating Damp?
Lateral damp is when moisture is allowed to enter the structure in a horizontal direction. Gravity then causes the downward movement of the damp into other areas. Penetrating damp can create isolated patches of dampness that increase in size after periods of heavy rain. The damp can occur at any level, unlike Rising Damp which usually rises from the ground up to 1.2 metres high. Lateral or penetrating damp is usually from a source too difficult to control and only an expert with a moisture metre detector will evaluate the difference in rising and lateral damp. Sometimes the problem may also require a plumber to pressure test the pipes to eliminate them as the problem.
Causes of Lateral Damp
▪ leaking water supplies or waste pipes
▪ fretted mortar joints
▪ defective brickwork
▪ failure of tile grouts in showers and other wet areas
▪ poorly functioning membrane in wet areas
▪ cracked render
▪ poor flashings
▪ defect in adjacent property outside the owners control
▪ air-conditioning or hot water system overflows can also lead to small localised patches of dampness.