Damp Proofing

Damp can affect any home for a number of reasons, if left untreated it will only get worse and more expensive to rectify.

Rising Damp

Rising damp is a major cause of decay to masonry materials such as stone, brick and mortar. Rising damp may show as a high-tide-like stain on internal finishes. When more severe, can cause blistering of paint and defective plaster.

Rising damp occurs within walls due to a breakdown of the existing damp proof course or the omission of damp proofing during earlier construction. Water from the ground rises up through the bricks and mortar of a building by a process known as capillary action. The height to which this moisture can rise depends on the nature of the wall and the evaporation rate. The average limit for rising damp ranges from 0.5 to 1.5 meters above ground level.

Treatment typically involves removal of skirting boards and any other fixtures and fittings, stripping back of the wall plaster and the installation of a chemical injection damp proof course (DPC). Height to which wall plaster should be removed would be assessed by one of our surveyors at the time of inspection. Re-instatement of plaster is then carried out in accordance with Harfords plastering specification.

When rising damp occurs, soluble salts are left behind. These are often hygroscopic, meaning they are able to absorb moisture from the surrounding atmosphere. It is for this reason that specialist plastering is such an important part of a successful rising damp treatment.

Penetrating Damp

Penetrating damp can occur for many reasons, such as faulty rainwater goods, defective flashings or possible plumbing  defects. These issues generally require the repair of the external defect together with some internal plaster repair. Where one of these defects has been longstanding, more substantial works are often required. Longstanding plumbing defects are a major cause of timber decay and can often cause outbreaks of dry rot.

Penetrating dampness will also occur where masonry is of single leaf construction, or where a cavity wall has become blocked with debris. The latter simply requires clearing and in worst cases some internal plaster repair.

Penetrating damp in single leaf construction can be remedied with the use of tanking or membrane systems

Contact us for information about inspections, reports and estimates.

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