Rising Dampness is a blight that can affect external and internal walls alike. The source of dampness in this case comes is from ground water. The bricks and mortar in the dry upper parts of the wall acts like a wick and draws water upwards.Well maintained, well constructed walls will have an efficient physical damp proof course (DPC) and are unlikely to possess dampness unless the damp proof course has in some way been compromised, for example;
Once the damp proof course has been compromised remedial action is required as soon as possible, continued presence of dampness on the upper walls will lead to deterioration of brickwork and internal plaster, décor.
The internal plasterwork in the home can break down quickly when exposed to such dampness. Replacement of plaster is usually required to some degree. This generally involves removal of the existing salt contaminated plaster* and render, applying a new sand & cement render with the appropriate waterproofing additive and then skimming with the appropriate finish plaster.
*Salt contaminated plaster should not be left in place, it will continue to absorb moisture created in the home and will frustrate attempts to correct the wall décor.
Identifying Rising Damp
Damp patches to external walls as shown may exhibit significant moss/lichen growth on external brickwork, water staining etc. Dampness may also be felt and seen on internal walls of the property, black mould due to resultant condensation, moisture and salt bands are all common tell-tale signs to look for.
All these conditions may of course not be due to rising damp, they could be the result of a simple water leak due to poor guttering, roofing etc. which results from the property suffering from penetrating damp a subject also covered on this site.
Rising damp, as aforementioned, is where water is drawn up from ground level by capillary action, the nature and physics involved with this form of dampness means it will rarely be present more than 1 metre from ground level. Signs of dampness above this level are commonly seen but will most likely be the result of condensation. A professional remedial survey is highly recommended in such cases as mistakes in diagnosis are commonplace, errors can result in unnecessary and costly works that fail to control the dampness.
Superior Coatings Painting Contractors provide free surveys and reports, with impartial, honest advice on the options available to the customer.
The Solution:
Remedial actions will vary according to the cause and the extent of damage caused by rising damp, some, maybe all of the following actions could be necessary;