Case Study:
Resolving Cavity Wall Insulation Dampness in Worthing

A property in Worthing recently experienced significant internal dampness issues caused by compromised cavity wall insulation.

This case study examines the problem, our diagnostic approach, and the effective solution implemented by Gavin Jones.

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The Problem

Upon inspection of the Worthing property, we identified telltale signs of dampness on the internal walls. The homeowner had noticed damp patches, cold spots, and early signs of mould growth on several walls. These symptoms are classic indicators of cavity wall insulation problems.

Further investigation revealed that cavity wool insulation had begun to slump and fall within the cavity space. This fallen insulation had subsequently become saturated with moisture. As the wool insulation absorbed water, it created a bridge for moisture to transfer from the external wall to the internal wall.

The Diagnosis

The primary issue was clear - the mineral wool insulation had deteriorated and fallen within the cavity. This material, while marketed as water-repellent, can actually absorb significant amounts of moisture when compromised.

The problem was exacerbated by the fact that once the insulation bridged the cavity gap, it created a direct pathway for moisture to travel from the outer wall to the inner wall. This is a common issue, especially in properties with:

Older cavity wall installations
Exposure to significant wind-driven rain
Porous external brickwork
Poor original installation

The Solution

Gavin implemented a comprehensive three-stage solution to address the problem:

1. Cavity Wall Insulation Removal

First, Gavin created access points by carefully removing bricks from the external wall. This strategic brick removal allowed proper access to the cavity space.

Gavin methodically removed all the wet, deteriorated wool insulation from the cavity. This process was crucial to eliminate the moisture bridge between the external and internal walls.

2. Cavity Inspection and Brick Replacement

Once all insulation was removed, Gavin thoroughly inspected the cavity to ensure it was completely clear. The removed bricks were then carefully reinstated and repointed to maintain the structural and aesthetic integrity of the external wall.

3. Waterproof Plastering

The final critical step involved applying specialised waterproof plastering to the internal walls. Rather than using standard gypsum plaster (which would remain vulnerable to residual moisture), Gavin applied damp-resistant plaster.

This specialised plaster:

Creates a breathable barrier against moisture migration
Allows the wall to dry naturally while preventing further dampness
Resists salt transfer that often accompanies dampness
Provides improved thermal properties
Reduces the likelihood of future condensation and mould growth

The Results

Following the completion of work, the property showed immediate improvement. The removal of the wet insulation eliminated the moisture bridge, while the waterproof plastering provided additional protection against residual dampness. The walls began drying out, and the internal environment of the home improved significantly.

The homeowner can now redecorate with confidence, knowing that the underlying issue has been properly addressed rather than simply covered up.

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How We Can Help

At G Jones Plastering & Damp Proofing, Gavin brings over 25 years of experience as a City and Guilds qualified plasterer and PCA Qualified Technician for damp proofing. We understand that cavity wall insulation problems require a comprehensive approach - not just treating symptoms but addressing the root cause.

If you're experiencing dampness, cold spots, or mould growth that might be related to cavity wall insulation, contact us for a professional assessment. We provide expert diagnosis and implement effective, lasting solutions tailored to your property's specific needs.