Chemical Damp Proofing
“we keep having paint peeling from the walls, we always tried to overcome this by painting the wall again and again however the result is the same. Now the question is how to get rid from this problem?” quote from Kenwood customer.
What is Damp Proofing?
Definitions
Damp proofing in construction is most commonly used to describe a protective measure applied to load bearing walls. In other words, it refers to the application of a water-resisting material or treatment to the masonry wall to form a damp proof course through the thickness of the wall.
The need for Damp Proofing
Without an effective damp proof course, water will rise up from the ground and into the walls of the building where it can cause damage. The water brings ground salts that are hygroscopic, which means they attract water vapour. The salt will continue to attract moisture from the air in to the walls, keeping the walls damp hence the need to prevent this by applying a salt resistant render such as Kenwood waterproof rendering system.
A damp proof course (DPC) is a barrier inserted into the fabric of a building to stop water passing from one place to another. This is typically on the horizontal plane, stopping water rising up from the ground by being drawn up the masonry by capillary action, though the masonry, to the inside. Physical DPC’s have taken many forms through the ages and one of the earliest forms was to use a layer of slate in the construction. Slate is still used but the less expensive plastic version is now more widely used in new build situations.
Chemical Damp proofing & membranes
A horizontal DPC is normally inserted 150mm above ground level, and used with a damp proof membrane in the floor which stops water from rising to any part of the ground floor from ground. It is usually a thick plastic strip inserted into the mortar between two courses of bricks or blocks. It can often be seen as a thin plastic line in the mortar near ground level.
In instances where the DPC has failed or where there is no DPC, a chemical DPC can be used in damp proofing the wall. One method of doing this is to drill a hole at regular distances in the masonry course and insert the dpc cream. The cream will then form a barrier that will prevent rising damp.
Kenwood often use this technique along with other methods of chemical injection and waterproofing using membranes and slurries etc.,