Heritage Domestic Property, Warnham – Replastering After Rising Damp Treatment

Heritage Domestic Property in Warnham, West Sussex

This is a privately-owned domestic property located in West Sussex. Parts of the building are over 500 years old but various extensions and modifications have been made over the years. The room that Surrey Hills Preservation were asked to look at was partly a solid wall brick construction and partly plastered timber lath.

The Problem

The main living room area of the property was suffering from significant rising damp issues. Some parts of the wall were showing signs of salt contamination and the plaster was crumbling and blistering. After the initial survey was completed, it was evident that a ‘pressure injection’ type rising damp was carried out in the past, which had now failed.

Visible salt contamination causing wallpaper to discolour and peel

Saturated plaster blistering and crumbling off the wall

After the previous rising damp treatment, it appears that the previous contractors had replastered the wall using a very dense and hard sand:cement render. The relatively impervious nature of the render seemed to be exacerbating effect of the rising damp by inhibiting the breathability of the walls.

The Solution

Preservation experts, Surrey Hills Preservation, decided that in order to solve the rising damp issue properly it was necessary to remove the older plaster, create an effective new DPC and replaster the walls using a heritage-friendly renovation plaster with a high lime and calcite content.

The old plaster and the sand:cement render beneath it was removed up to the height of 1 meter. The hard render had caused some damage to the bricks beneath it during removal. Once the walls had been taken back to the bare brick, a treatment of the BBA-approved high-strength Dryzone Damp-Proofing Cream was carried out. Once Dryzone Damp-Proofing Cream had cured to create a new chemical DPC, the walls were able to be replastered.

Applying Dryzone Hi-Lime Renovation Plaster to the wall

Dryzone Hi-Lime Renovation Plaster was chosen to carry out the replastering. The plaster blend which contains a high proportion of natural hydraulic lime and calcite is highly breathable, quick drying and suitable for heritage applications. The material is less dense than the sand:cement renders that are often used in rising damp treatments and, as a result, is non-destructive to the underlying brickwork.