Rising Damp is a common problem in older buildings. Moisture rises up the wall by capillary action depositing salts and damaging the wall finishes.

However Rising Damp is less common than commonly thought and dampness at the base of a wall may be due to other rising damp problems such as Penetrating Damp and Condensation. More often than not the cause is due to bridging of an existing Damp Proof Course by high ground levels.

Detecting Damp in the Home

Electronic moisture meters are commonly used to diagnose Rising Damp but these commonly give false high readings with certain paint and wall finishes, fail to diagnose Condensation and Hygroscopic Salts (from an historic problem).

If high Damp Report Readings are given with a moisture meter then further investigation should be carried out. Mortar Sampling of the masonry is the only accurate way of quantifying the Absolute Moisture Contents and Hygroscopic Salt levels in the masonry.

Damp Proof Course

The solution to rising damp is usually to inject a Chemical Damp Proof Course, and to re-plaster the internal walls with a waterproof layer up to 1.2 metres high. Damp proof course usually comes with a 10, 20 or even 30 year guarantee.

Ground floor slabs are equally likely to be affected by rising damp. It is only modern properties which have proper Damp Proof Course Membranes beneath the floor slabs.

Older properties often relied on tile finishes to control rising damp. If there is a rising damp problem with a ground floor it is either controlled with an impermeable covering such as Vinyl Sheet Flooring, or the slab must be replaced with a new one incorporating a damp proof course membrane.

Identifying Penetrating Damp

Penetrating damp is caused by moisture which penetrates through the roof or walls.

Roof problems are usually evident. Damp penetrating through walls, which includes flashings at roof and chimney abutments, is usually quite evident, but it is usually very difficult to pinpoint and cure the precise cause of the problem and very often there is no quick or easy solution.

Penetrating damp can sometimes be caused by gutter or roof problems which allow rainwater to spill onto and saturate areas of wall.

Dealing with Condensation

Condensation is the third type of damp. This is usually caused by the lifestyle of the occupants, rather than a defect with the property. Lack of ventilation and a tendency to use the radiators for drying clothes are common causes.

A typical Damp Report will identify those (readily accessible) areas where damp is present and will identify the cause, along with recommendations for any necessary repairs or remedial works.