Council Property, Crawley – Protecting Cavity Wall Insulation

This rental property is owned by the Crawley Borough Council. It was built in the mid-1960s using a standard cavity wall construction. The building is split into two semi-detached homes, a standard configuration for properties in the area. The building does not face the road directly, leaving the gable end exposed to the elements.

The Problem

Damage to the cavity wall insulation caused by penetrating damp

The building had been subject to an installation of cavity wall insulation. The intense rainfall of the previous winter and deterioration of the building materials of the property had resulted in water penetrating the brickwork and severely dampening the cavity wall insulation.

The damp cavity insulation transmitted a large amount of water through to the interior wall. The décor was spoiled and the living environment for the occupants was uncomfortable. The damp patches were not drying out, even during the warm and dry summer months. Crawley Borough Council surveyed the situation.

The Solution

The report by the Crawley Borough Council surveyors recommended that the best course of action was to remove the cavity wall insulation, repoint the gable end, install new insulation and then treat the wall with Stormdry Masonry Protection Cream.

Saturated mortar caused by penetrating damp

Downs Energy, insulation and energy saving experts, performed the removal of the insulation. A proper assessment of the condition of the wall was undertaken after the damp cavity wall insulation had been removed. The mortar of the brickwork had become severely degraded over the years, which in combination with the already porous brickwork had led to the penetrating damp problems.

Repointing the brickwork with Stormdry Repointing Additive

The wall was thoroughly cleaned and the damaged mortar raked out, using Stormdry Repointing Addtive No.1. It is always advantageous to use Stormdry Repointing Addtives before the application of Stormdry Masonry Protection Cream. They ensure a more flexible and complete bond with the brickwork reducing cracks that normally occur during the curing process.

Applying Stormdry Masonry Protection Cream to the outside of the house

After the repointing had been completed and allowed to cure and dry out, new and more robust cavity wall insulation was installed and a coat of Stormdry Masonry Protection Cream was applied to the wall. The breathable coating will protect the wall from further water penetration for a BBA-approved 25 years whilst still allowing any leftover moisture to evaporate in the form of water vapour.