Rising Damp Services

What is Rising Damp?

Rising damp is the common term for the slow upward movement of water in the lower sections of walls and other ground-supported structures, by capillary action. Although rising damp of up to 5 meters in height has been observed the height of rise is typically much lower and is rarely above 1.5m.

In simple terms rising damp occurs when ground water travels upwards through porous building materials such as brick, sandstone, or mortar, much in the same way that lamp oil travels upwards through the wick of a lamp. The effect can easily be seen by simply placing a piece of porous brick, stone, or mortar in a shallow tray of water and observing how the water is absorbed into the porous material and is transported above the water line. Rising damp can be identified by a characteristic “tide mark” on the lower section of affected walls.

This tide mark is caused by soluble salts (particularly nitrates and chlorides) contained in the groundwater. Due to the effects of evaporation these salts accumulate at the “peak” of the rising damp. The plaster becomes hydroscopic due to the effervescent salt contamination. Besides treating the cause of the rising damp, the contaminated plaster also needs to be removed and replaced with a salt inhibiting render.

Rising damp in historical buildings is particularly challenging, needing specialised treatment as the substrate is vastly different from that of modern homes.

Our Treatment Explained

On the inside, the resultant hydroscopic damp needs to be treated by removing the contaminated plaster, the underlying brick work sealed with a waterproof sealant and quartz cream injections done to prevent rising damp. The wall is then re-plastered with a salt retarding mortar.