We don’t know how many Listed Buildings there are in the UK, but Historic England estimates that there are approximately 400,000 in England alone. Many of these are located in city centres and areas where the manufacturing industry once thrived – with property developers considering how they can be refurbished for 21st century use. For example, Battersea Power Station in London is one of the biggest regeneration projects in Europe, being turned into luxury flats and retail outlets for businesses.

Listed buildings are popular with businesses who often desire an office in a well-recognised, focal point. However, conversion of these buildings does require close collaboration between Architects, Engineers, Surveyors and their owners, so that damp issues never become a problem. These structures have faced the weather’s elements for a long time and poor design detail could cause lasting damage which requires rectification.

Identifying a Damp issue early and taking measures to deal with it, before it causes too much damage, is always the best policy. Fortunately, there are some tell-tale signs to look out for. Damp characteristically leaves stains, dark patches and discolouration on walls and can sometimes lead to mould forming. In confined and unventilated spaces, is usually accompanied by an unmistakably musty smell. Decayed skirting boards and damaged wall plaster within properties are also often a sign. There are three main types of damp to look out for; Condensation, Rising Damp and Penetrating damp.

• Condensation in listed buildings

Condensation occurs where moisture  evaporates into the atmosphere and then condenses on a cold surface such as an external wall. It is most common between October and April and it can be found in properties of any age, size or design. While condensation is the most common damp problem in a building, preventing it requires a change in habits, such as keeping rooms at an even, moderate temperature and opening the windows to increase ventilation. To some people this may sound counter intuitive so it can be more beneficial to manage and control condensation by using advanced condensation control methods such as installing a heat recovery or positive input ventilation unit.

•  Rising Damp in listed buildings

Rising damp occurs when moisture is drawn upwards through the mortar and masonry of a building by capillarity. Any masonry type can be affected but the more porous building materials such as brick and sandstone are most susceptible. From the 1900’s onwards most buildings in the UK incorporated a damp proof course (often referred to as a DPC) that acts as a horizontal barrier to water rising. However, if you are maintaining an older building then this might not be the case, as a damp proof course will not have been included in its construction or the existing one may have failed. This is where Peter Cox can help, installing the appropriate system for you by inserting a new DPC and remedying any damage to the damp affected wall plaster.

• Penetrating Damp in listed buildings

Penetrating damp is most often caused by exposure to prevailing winds, which can drive rain into the masonry, and is most pronounced on buildings with solid rather than cavity walls. Property defects such as defective pointing, gaps around windows, leaking roofs and gutters or even flower beds banked up against the side of the building can all lead to moisture entering the building. The most effective way to protect a property from penetrating damp is to firstly rectify such defects and then apply Thermotek a breathable water repellent cream to the exterior of the property.

Top tips to prevent damp in listed buildings

• Ensure that external ground levels are a minimum 150mm below the building’s current damp proof course
• Regularly check gutters, downpipes and drains to ensure there are no blockages or leaks
• Inspect flashing on your property’s roof and seals around windows to ensure they  prevent water from entering the building 
• Apply a breathable water repellent cream  to the building’s exterior
• Keep your property ventilated, even for just one hour in the morning during colder months will help reduce the risk of condensation 

Need professional help damp proofing a listed building?

If you have been through these preventative measures and damp issues are prevailing, or perhaps getting worse, then call in the experts who can fully investigate and diagnose the cause of your problems, as well as  provide options for ways to deal with them.  Find out more about our services here.

By Richard Walker, National Technical and Development Manager at Peter Cox

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