Rising damp is an affliction that can affect both internal and external walls. The source of the dampness, in this case, comes from groundwater. The bricks and mortar in dry upper parts of the wall act like a wick, drawing water upwards from the ground, resulting in damp. 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 been compromised in some way.
Rising damp in London buildings and properties is a fairly common problem, especially in older buildings or places with poor ventilation.
How Can a DPC Become Compromised?
- Due to age or original use of poor materials
- External materials such as a patio, paths, soil or rubbish abutting against an external wall allowing the DPC to be bridged
- Existing DPC being breached by home improvements, such as adding a porch, conservatory or adjoining wall
- Materials within the cavity of a cavity wall construction
Identifying Rising Damp
- Damp patches on external walls may exhibit moss or lichen growth and water staining on the outside brickwork
- Dampness may be felt and seen on the walls internally at low levels (from floor level up to 1 to 1.5 metre high in general)
- Moisture and bands of salt to internal plaster
What Can Garratt’s Damp & Timber Do About Rising Damp?
Once the damp proofing course has been compromised, remedial action is required as soon as possible because continued presence of dampness will lead to deterioration of the brickwork and internal plaster or decor.
Internal plaster in the home can break down quickly when exposed to dampness. This can look unsightly and replacement is sometimes required for effective treatment.
After a survey to identify the type of damp concerned, some or possibly all of the following actions may be necessary:
- Bridged DPC: Requires the removal of the soil or bridging materials to ensure a minimum 150mm clearance below the DPC, dependent on internal floor levels/construction
- Injection of a chemical damp proof course, close to the original DPC in most circumstances
- Replacement of joists or rotten internal flooring in contact with the damp
- Removal and replacement of damaged and/or salt contaminated internal plastering
However, you should be wary, as many of these signs can also point to a different diagnosis. Water ingress from defective render, poor guttering, pipes and roofing (penetrating damp) plus plumbing leaks will also exhibit moisture patches. These will not be cured with a damp proofing course. Rising damp quotes from professionals like Garratt’s Damp & Timber Ltd are the best way to ensure your home is treated in the best and most appropriate way.
