Victorian House, Manchester – Replastering Salt‑Contaminated Chimney

Background

This unusual Victorian property is located in Manchester. The property was previously part of a terraced row of houses. The original construction consisted of 225 mm solid exterior brick walls with 112 mm party walls, which formed part of the chimney enclosures. The floors are suspended timber and the roof is a traditional timber construction. The connected houses to the right were demolished, leaving this and the neighbouring property as a pair of semi-detached houses.

The Problem

The contractors who carried-out the modifications to the building had attempted to provide some protection from the elements by constructing a second outer-leaf brick wall on the new gable end. However, these works had been finished to a poor standard.

As a result, one of the interior walls (which used to be a party wall between terraced properties) had been subjected to large amounts of rain penetration via the roof line and chimney. Moisture ingress on the interior wall had caused hygroscopic salts from the chimney stack to migrate to the decorating surface.

The Solution

PCA-approved building refurbishment experts, Olympic Construction Ltd, were brought-in to diagnose the problem and provide a long-lasting solution. Following an extensive survey, Olympic Construction carried-out extensive reconstruction on the gable end of the property. The reconstruction work ensured that the roof line was fully sealed from moisture ingress. Afterwards, they replastered the interior using a combination of Drybase Flex and plasterboard.

Drybase Flex Membrane is a strong and flexible fleeced polypropylene membrane for application to walls that have been affected by dampness and salt contamination. It is quickly and easily applied directly to walls using Drybase Flex Adhesive. Once applied, the system will resist damp and salts, stopping them from reaching any new decorative surface and allowing the direct application of plaster.

Adrian Dawson, the Managing Director of Olympic Construction, explains the process, “Once we’d replaced the roof and rebuilt the outer wall, we had to contain the hygroscopic salts on the inner walls so they didn’t resurface and spoil any decorations. We could have done that using a plastic studded membrane, but we chose the Drybase Flex replastering system because it bonds to the brickwork, almost like wallpaper. That means there are no voids, so if water ever does penetrate the brickwork, the Drybase Flex system will stop any water or salts leaking back into the structure”.

Adrian continues, “We chose to work with the Drybase Flex system because it is produced in accordance with ISO 9001 and ISO 14001 quality and environmental management systems, leading to a long service live. It also allows for lightweight plaster systems to be applied, which results in higher U-values being achieved”.

After the Drybase Flex application, plasterboard was applied directly to the membrane using standard “dot & dab” dry-lining techniques. The walls can now be decorated and the property owner will enjoy a damp-free home.