Case Study:
Problem Solved! Rising Damp in Worthing
This case study details a comprehensive damp-proofing project undertaken at a residential extension in Worthing.
The property was suffering from two distinct but related issues: rising damp caused by elevated external ground levels, and mould growth resulting from condensation problems. Our approach involved implementing a dual solution strategy using a fleece membrane system combined with a chemical damp proof course (DPC) installation.
The Problem
Rising Damp Issues
The extension was experiencing significant rising damp problems primarily due to high external ground levels surrounding the property. This allowed groundwater to rise through the porous masonry via capillary action, carrying ground salts (nitrates and chlorides) into the walls. These hygroscopic salts naturally absorbed and retained moisture, causing the walls to become highly saturated and leading to visible damage on internal surfaces.
Condensation and Mould
In addition to the rising damp, the property was suffering from mould growth on the walls caused by condensation issues. The cold wall surfaces were creating ideal conditions for moisture in the air to condense, leading to persistent dampness and subsequent mould development. This not only affected the aesthetic appearance of the extension but also posed potential health risks to the occupants.
The Solution
Chemical DPC Installation
To address the rising damp, we installed a chemical damp proof course (DPC) through injection.
This involved:
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Drilling a series of holes along the mortar bed joint approximately 150mm above external ground level, following BS 6576:2005+A1:2012 guidelines.
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Injecting a high-performance silicone-based damp proofing cream into these holes at regular intervals.
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Allowing the chemical to penetrate the masonry and create a continuous water-resistant barrier.
The chemical DPC works by filling the capillaries in the masonry with water-repellent compounds, effectively blocking the path of rising moisture. This creates an impermeable layer that prevents water from ascending through the walls, thereby stopping the rising damp at its source.
Fleece Membrane System Application
To combat both the existing damp conditions and prevent future condensation issues, we installed a flexible polypropylene fleeced membrane system:
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The walls were prepared by removing any loose material
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Drybase Flex adhesive was applied to the wall surface in sections of approximately 1m²
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The 1mm flexible polypropylene fleeced membrane was attached to the adhesive
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Adjacent sections were overlapped by at least 50mm to ensure continuous protection
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The membrane was allowed to cure overnight before applying new plaster finishes
This membrane system provides multiple benefits:
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Creates a physical barrier preventing damp and salts from reaching decorative finishes
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Provides a warmer surface temperature, reducing the risk of condensation
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Offers an excellent surface for plaster to adhere to without requiring drilling or plugs
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Accommodates awkward shapes and small indents due to its flexible nature
Results and Benefits
Elimination of Rising Damp
The chemical DPC injection successfully created a horizontal barrier that prevents groundwater from rising through the walls. This has effectively stopped the capillary action that was drawing moisture and salts upward into the masonry, addressing the root cause of the rising damp problem.
Resolution of Condensation Issues
The fleece membrane system has significantly improved the thermal properties of the wall surfaces. By creating a warmer surface, the risk of condensation forming has been dramatically reduced, eliminating the conditions that were promoting mould growth. The residents now enjoy a drier, healthier living environment.
Long-term Protection
The combined solution provides comprehensive, long-lasting protection against both rising damp and condensation issues. The chemical DPC offers protection for up to 25 years, while the membrane system provides a permanent barrier against moisture and salt contamination for the structure's life.
At G Jones Plastering & Damp Proofing, Gavin's expertise in diagnosing and treating various damp issues ensures that each project receives the most appropriate treatment solution. With over 25 years of experience and PCA qualification as a damp proofing technician, Gavin can identify the specific causes of damp problems and implement effective, long-lasting remedies.
If you are experiencing similar issues with rising damp, condensation, or mould in your property, contact us today for a professional assessment and tailored solution.