The cost of rising damp

Dampness is likely to be one of most homeowners' property condition concerns, whether spotted in an existing home or a worry about the condition of a property that is being purchased. Most people will not be prepared to tolerate noticeable dampness, which can damage decorations, spoil furnishings and might also lead to more serious problems. Dampness can also give rise to health problems, so how to treat damp is obviously an important question. This is one of the most frequent questions asked of Chartered Surveyors, either when surveying a property prior to purchase or when carrying out an e.surv PropertyCare report on a client's existing home.

The surveyor will be conscious of the fact that dampness can be caused by many different building defects, each requiring a different property care solution. All buildings are damp to some extent and that some materials must retain some moisture to remain structurally stable. In some situations, therefore, the question should not be "how to stop damp". Instead, the correct property care solution question might be "how to manage damp"; keeping the problem at an acceptable level so as not to damage the property or cause the occupier problems.

Rising damp does exist. It is a real and actual problem, although it is often misdiagnosed and it is also true that inappropriate or unnecessary damp treatment works are regularly recommended, often by those whose sole interest is in selling their product or services. Before the late 1900s damp proof courses were rare and as most building materials are porous to some extent, capillary action will draw water from the ground. Later properties usually have some form of DPC but these can deteriorate over time, becoming a less effective barrier to dampness. The absence or failure of a DPC can be dealt with by a number of property care solutions, including the physical insertion of a replacement DPC or the injection of chemical treatment. Replastering is usually required to eliminate salts which will otherwise continue to absorb atmospheric moisture. Other alternatives such as ceramic wall vents inserted are widely advertised but their longevity is unproven.

Other problems can give symptoms similar to rising damp but will require different property care solutions. External soil or paving covering the DPC will allow dampness to penetrate through the wall, in which case all that may be needed is to lower the ground level. Debris with wall cavities bridging the DPC, and problems with the damp proof membrane in solid ground floors can also make the lower parts of the walls damp, but will not be cured by "damp treatment".

At upper levels penetrating damp can be caused by a number of problems; defective roofs, bridged cavity wall ties, poorly sealed window frames and so on. The most obvious signs of dampness might not be a "property condition" issue at all. Black mould to internal surfaces is normally an indication of condensation and this is usually the result of life style issues; excessive moisture vapour, inadequate ventilation, erratic heating etc. Inherently damp properties will be more prone to condensation and dealing with the problem might, therefore, demand several property care solutions. Improving insulation will also help and Green Deal loans should soon be available to help with these improvements.

There is no single solution to dealing with the problem of dampness. It is vital to correctly diagnose the nature of the problem and to identify the most appropriate property care solution. Seeking advice from a Chartered Surveyor will ensure that homeowners do not waste money on inappropriate or possibly damaging repairs.