Listed Building Repairs – Damp Proofing Essentials

Our experts are regularly recruited to perform a whole host of listed building repairs as, with the exception of Devon, Kent has more listed buildings than any other region in England.

With nearly 18,000 listed buildings spread across the county, the range of problems we are presented with is vast, and our team have seen it all.

By their nature, listed buildings use different materials and are subject to strict planning regulations that protect our heritage for future generations. Our team has perfected various techniques to solve the property’s dampness issues.

Understanding Damp and its Impact

The damp that affects listed buildings is the same damp that impacts more modern properties; however, these new builds are built to withstand the effects of water.

Rising damp is naturally occurring, and a common problem in listed buildings. Rising damp is the movement of water, by capillary action, up the wall of a property, leaving salt marks up the internal decor.

In new build houses, there is often a cavity between the external and internal walls. The water will try to bridge the cavity to the interior wall, and that is when you will start to see the impact on the decoration. However, listed buildings often have just one layer of brickwork and porous masonry.

Penetrating damp is the movement of water through walls, impacting all materials in its way and again affecting the internal decor of a property.

Condensation is the build-up of water droplets on a cold surface when humid air hits it. It is often in a bathroom or kitchen with high levels of steam. Many solutions are not as effective in listed buildings, resulting in a build-up of moisture which is the perfect growing condition for mould.

The Impact of Damp

Damp can have a devastating impact on any building, and listed buildings are no different. Given the nature of the materials used and some of the restrictions around solutions, implementing listed building repairs can be more challenging. But it must be dealt with as soon as possible.

Damp can lead to structural issues, affecting masonry and timber exposed to prolonged dampness. It can also impact the health of the occupants if dampness goes unchecked.

Listed Building repairs

Why Listed Buildings Are Susceptible to Damp

By their nature, listed buildings were constructed according to different principles with alternative materials. While they have stood the test of time, given the potential for alterations over the years and changes in technology, as well as the noticeable wear and tear of, in some cases, hundreds of years, they are prone to issues with dampness.

New buildings are created with an inbuilt membrane and two brickwork layers that form a cavity that water theoretically can’t cross. These practices allied to the cement mortar improve the defence against dampness from outside and the ground beneath.

Listed buildings typically have solid walls with lime mortar which are porous. This approach is known as breathable construction, meaning the water can permeate the walls but evaporate just as quickly. In a temperate climate like Kent, this can be very successful.

Kent’s climate, compared to other areas of the country, is reasonably temperate. The average yearly rainfall between 500mm and 600mm means it is one of the country’s driest areas. However, the area is also prone to flash flooding during the wet seasons as the ground reaches saturation between December and March.

So while conditions are favourable in Kent for listed buildings, as with all things, the effects of time can impact efficiency, which is where support with damp proofing is required.

Damp Proofing Regulations for Listed Buildings

Making any alterations to listed buildings is tightly controlled by local authority building regulations and requires permission to make any changes.

Using like-for-like materials to maintain the property is usually permitted without permission (but always best to check first).

However, finding a solution for damp proofing will almost certainly involve altering and adding new materials to the building. Making these changes without permission from the relevant authorities is a criminal offence. The liability can lie with the person undertaking or authorising the work, so it is better to get the appropriate permission in all cases.

Common Damp Proofing Methods

Once you have acquired the appropriate authorisation and identified the problem, here are a few listed building repairs that can be used to tackle dampness.

Prevention Is The Best Cure

If there is a way to avoid working on the structure of the building, then this should be the first approach.

Better ventilation and heat management can reduce the likelihood of condensation, particularly around areas of high moisture content, like the bathroom and the kitchen. So if windows can be opened in summer and a more consistent level of heating can be achieved, then this reduces the temperature imbalance in the property.

Another common issue in listed buildings is the changes made outside around the base of the building. Whether that is a new driveway or alterations to the gardens that raise the ground level above the damp-proof course, if there is one. This can lead to rising damp, a common complaint when visiting listed buildings.

Returning this to its original levels will help remove the bridge the water uses to move into the wall.

Damp Proof Course

The alternative to this is repairing or inserting a new damp-proof course (DPC) into the wall. There are damp-proof courses in keeping with the traditional nature of the buildings, such as a slate DPC, but all work will be checked and officially approved before it takes place.

Vertical Air Gap Membrane

In some scenarios, we have used a vertical air gap membrane. It creates a good balance between preserving the existing building, given the minimal fixings used, and decoration, providing the right finish while allowing the original structure to remain damage-free.

Waterproof Cream

There are also now options to use a waterproof cream that can be applied to the porous brickwork that will protect against the moisture in the ground. However, we would always guard against this and ensure it is officially approved.

Faulty Rainwater Goods

Finally, again keeping with the prevention theme. Often problems are caused by faulty rainwater goods that allow water to penetrate the brickwork from above. The problem could be a broken downpipe, render cracks, or poorly fitted windows.

Therefore, the obvious solution is repairing the offending issue and the likely damaged decor inside the house. These sorts of repairs should stop the dampness from developing. Still, there will be some investment internally to repair and replace the existing decor, which may require permission, depending on the severity of the alterations.

Listed Buildings Repairs

Given the sheer volume of listed buildings in Kent, the call for listed building repairs is one we answer regularly.

When you come across dampness in your listed property, it can be a major concern. There is more to consider than a straightforward repair with different building materials and planning regulations to consider.

So starting with a full assessment of the situation will help give you the peace of mind that any solution suggested should solve the problem. And, while there are a range of fixes you can implement around repairs and ventilation, partnering with an expert is critical if you want to find an appropriate solution.

Choosing the Right Damp Proofing Specialist

Making listed building repairs requires the right level of expertise. Not everyone is qualified and fully understands the legal implications. With so many listed buildings in Kent and our many years of experience, the South East Timber and Damp team is well-placed to deal with the damp issues you face.

Find out from our clients how we have supported them and delivered solutions for a whole host of problems. And if you need support with your property, get in touch today, and we will be more than happy to help.

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