The Damp
This particular client came to us after months (possibly years) of frustration. There were patches of damp that kept showing up around the lower parts of the internal walls. Paint was flaking, plaster was bubbling, and unsightly patches were all over his house. No matter what he did to get rid of it, the damp stayed stubbornly put. So eventually, he called us for help.
At first glance, the outside of the property didn’t look too bad. But once we investigated properly, we discovered that four different issues, not just one, caused the damp. We found:
• Failed render on the external walls, allowing water to soak through the outer lead of the masonry.
• At the lower level of the wall, the cavity had become breached by a buildup of mortar and rubble. This was likely left behind after the original construction.
• Poor installation caused the cavity insulation to become saturated over time.. It was holding moisture against the inner wall like a sponge!
• Applying the exterior render below the damp proof course bridged it and allowed moisture to bypass this essential barrier.
So while it might have looked like a bit of isolated damp on the surface, the root cause was much deeper, and a combination of a few different factors.
Breached Cavities – Why Do They Matter?
For anyone who isn’t familiar with how cavity walls work, here’s a quick rundown. Builders make them with two layers of masonry separated by a gap called the cavity. This cavity isn’t just empty space though – it’s a vital moisture barrier. When it’s working properly, it stops water that gets through the outer brickwork from making it to the inner layer and into your home.
So, when that cavity is breached (whether by debris, failed insulation, mortar snots or something else), it creates a clear path for moisture to travel straight into your living space. From there, it doesn’t take long for damp to cause real, visible damage.
Our Approach
Once we identified the root issues causing the damp, we developed a clear and detailed specification for the remedial works. No guesswork, and no temporary fixes. Just a practical, long-term plan based on evidence and tailored to the property.
Sadly, we’re often asked to look at properties where repairs have already been done, and the issues have stuck around or even got worse. We then find that the repairs done (which are often expensive) were completely inappropriate, and have missed or ignored the root cause.
For this specific job, our spec included:
• Stripping away all failed render, including sections that had breached the damp-proof course.
• Carefully opening up the wall to remove the cavity debris and the saturated insulation.
• Replace that insulation with a modern blown system, treated with a hydrophobic chemical that actively repels water. This will maintain thermal performance without trapping more moisture.
• Internal improvements, including re-plastering and decorating the affected area, and replacing the kitchen (as this was the room most affected).
To ensure good value for money and protect our client’s investment, we then managed a competitive tender process, bringing in trusted contractors to price the job. This gave the client options and ultimately helped them select a high-quality contractor for the work.
The Result
When it was all finished, the transformation was truly remarkable. We replaced all of that external render with a new, properly designed system, allowing for thermal movement at known weak points. That means the render won’t crack or fail prematurely, and that the finish will look great for years to come. Inside, the property is damp-free, warmer and a much more comfortable place to live. And cosmetically, the place looks fresh, clean and well-maintained. You wouldn’t even know it had suffered from damp at all!
Most importantly, our client can now relax knowing the root of the problem has been properly dealt with, not just patched over.
To Recap
So, what’s the big takeaway? Why are we telling you this story?
Damp is usually just the symptom. The true cause, and why it keeps coming back, is just under the surface. It’s inside the wall structure, in the detailing, or even in the materials first used decades ago to build your home. If you’re seeing signs of damp, particularly around the base of your walls, don’t just assume it’s condensation. It could easily be a sign of a breached cavity, a bridged damp-proof course or some failed insulation – all of which you need a professional with the right approach to diagnose and fix properly. Getting a survey at the first sign of damp from a professional who understands building pathology can save you significant money and stress in the long run.
At Harrison Clarke, that’s us! We have decades of experience in all things damp, which means we can not only identify where the damp is, but the root cause and best way to resolve it. If you need any help or advice with damp, or would like us to take a look at your property, please give us a call on 02381 55 00 51 and speak to one of our experts.
For more expert advice on surveying and property matters, check out our range of informative videos on our website or YouTube channel. Harrison Clarke Chartered Surveyors is here to guide you every step of the way!
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