Carleton Surveyor Case Study: Bridged Damp Proof Course in a Detached House, Carleton
Overview
During a recent RICS Level 2 survey of a 1970s detached property in Carleton, an issue was identified concerning a bridged damp proof course (DPC) which has led to elevated moisture readings on the internal face of an external wall. This case study aims to provide a detailed explanation of the problem, its implications, and recommended actions to rectify the issue, serving as a guide for potential home buyers.
Survey Findings
During the inspection, moisture readings were taken along the internal face of the external walls. Elevated moisture levels were detected, particularly on the ground floor. Further investigation revealed that the damp-proof course, designed to prevent moisture from rising through the walls, has been bridged.
Understanding the Problem
A damp proof course is a crucial element in the construction of a building, typically a horizontal barrier built into the walls to prevent moisture from rising by capillary action from the ground. In this case, the DPC has been compromised, or “bridged,” meaning that there is a continuous path for moisture to bypass the DPC and rise up into the walls.
Causes of Bridging
Several factors can lead to a bridged damp-proof course:
1. External Ground Levels: The ground level outside the property may have been raised over time due to landscaping or the addition of pathways and patios, allowing moisture to bypass the DPC.
2. Internal Floor Levels: Changes to the internal floor levels, such as the installation of new flooring that raises the level above the original DPC, can create a bridging point.
3. Debris Accumulation: Accumulation of debris or mortar droppings in the wall cavity can provide a bridge for moisture to rise above the DPC level.
4. Defective or Poor Workmanship: Original construction defects or subsequent renovations that disturb the DPC can lead to bridging.
Implications
The presence of elevated moisture levels due to a bridged DPC can lead to several problems:
– Structural Damage: Persistent dampness can weaken the masonry and timber structures, leading to decay and potential structural failure.
– Health Risks: Damp environments promote the growth of mould and mildew, which can have adverse effects on health, particularly for individuals with respiratory issues.
– Aesthetic Damage: Damp can cause unsightly staining, peeling paint, and wallpaper damage.
Reduced Property Value: Damp issues can significantly reduce a property’s market value and appeal.
Carleton Surveyor Recommendations
To address the issue of the bridged DPC, the following steps are recommended:
1. Lower External Ground Levels: Ensure that external ground levels are at least 150mm below the DPC. This may involve regrading soil, removing paving, or installing drainage channels.
2. Check and Adjust Internal Levels: Ensure internal floor levels are consistent with the original design and do not bridge the DPC.
3. Cavity Wall Inspection and Clearance: Inspect the wall cavities to remove any debris or mortar that may be causing bridging. This might require professional assistance to avoid further damage to the structure.
4. Repair or Replace DPC: In cases where the DPC is damaged, it may be necessary to inject a chemical damp proof course or install a new physical DPC. This should be carried out by a specialist contractor.
5. Regular Monitoring: Once remedial works are completed, moisture levels should be regularly monitored to ensure the effectiveness of the solutions.
Conclusion
The discovery of a bridged damp proof course in a detached house in Carleton is a serious issue that requires prompt and effective remedial action. As a potential home buyer, understanding the implications and necessary steps to address this problem is crucial. Engaging with qualified professionals to assess and implement the recommended actions will help ensure the property’s integrity and value are maintained.
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Disclaimer: The information contained in this blog is provided for general guidance only and does not constitute legal, financial, medical, or other professional advice. No warranty, express or implied, is given as to the accuracy or completeness of the information. Reliance on any information provided is at your own risk.
