Victorian Residential Property, Brighton – Treatment of Chimney Damp

This Victorian semi-detached residential property is located in the large seaside town of Brighton, East Sussex. The house was purchased a few years ago by the owners and has been undergoing general renovations.

The Problem

Damp patches and salt staining were occurring on the chimney breasts in the upstairs rooms of this late Victorian house. The owners wanted the problem to be dealt with before refurbishing the rooms. The source of water ingress was traced to defective flashings and pointing on the chimney stack. These were rectified by a specialist roofing contractor.

Monitoring of the chimney breasts over several months demonstrated that the chimney breasts were starting to dry out – even after periods of extremely heavy rain during the winter of 2013 / 2014. It was therefore decided that the source of moisture had been successfully identified and dealt with.

Unfortunately damp patches on chimney breasts can be very persistent, even when the source of dampness has been dealt with. This is because chimney breasts are usually contaminated with moisture-attracting hygroscopic salts that have built up in the chimney structure as a result of the burning of coal over many decades.

If the wall is simply repainted or replastered using a standard gypsum plaster, these salts will usually migrate to the wall surface resulting in the return of decorative spoiling.

The Solution

The Dryzone Express Replastering System was originally developed as a method of replastering salt-contaminated walls as part of a rising damp treatment strategy. However it is just as applicable to replastering over salt contaminated chimney breasts provided that any water ingress has been identified and dealt with.

Its key advantages are:

• Applied more quickly than traditional methods
• Can be redecorated over more quickly than traditional methods
• Breathable

In this example, the Dryzone Express Replastering System was used in conjunction with a skim coat of plaster which was dry after just three days. A faster option would have been to use dry jointing instead of a skim coat – allowing redecoration to take place the same day.

A dry wall surface to a high decorative standard was achieved much more quickly than would have been possible using traditional methods. Hacking off of the plaster, installation of the Dryzone Express Replastering System, and application of the skim coat were carried out in a single day. Painting took place three days later.