The Myth of Rising Damp and Why You Might Not Need a Chemical Damp Proof Course

If you’ve ever had a damp patch appear on your walls and wondered what’s causing it, chances are you’ve heard of “rising damp” as the likely culprit. It’s a term many property owners are all too familiar with, often leading to costly treatments, like chemically injected damp-proof courses (DPCs), to “fix” the problem. However, rising damp may not be the issue at all.

In a surprising revelation, Stephen Boniface, former chairman of the construction arm of RICS (Royal Institution of Chartered Surveyors), made a bold statement in an article for The Architects Journal. According to Boniface, “true rising damp is a myth,” and chemically injected DPCs are a “complete waste of money.” This assertion challenges the status quo and raises the question: Are we misdiagnosing damp problems and wasting money on unnecessary treatments?

What Exactly is Rising Damp?

Rising damp is traditionally defined as moisture that rises from the ground through capillary action, travelling up walls and causing damage along the way. It’s typically seen in older buildings, where the dampness can lead to peeling paint, mould growth, and structural damage.

To combat this, many buildings were constructed with a damp-proof course (DPC) – a barrier built into the wall to prevent moisture from rising. But when damp patches appear, some property owners are often advised to inject a new chemical DPC to “stop” the rising damp. It’s a solution that’s both costly and disruptive.

The Myth of Rising Damp

Boniface isn’t the only one questioning the existence of rising damp as a widespread problem. Elaine Blackett-Ord, Chair of the Register of Architects Accredited in Building Conservation, also spoke out against the idea of rising damp being a common issue. She emphasised that in her experience, true rising damp is exceedingly rare, and that the industry surrounding it is, unfortunately, driven more by profit than actual need.

“The industry built around rising damp is worth over £200 million per year,” Blackett-Ord pointed out. And while it’s clear that some damp-related issues exist, rising damp is often misdiagnosed or exaggerated for financial gain.

Jeff Howell, a qualified bricklayer and author of The Rising Damp Myth (2008), adds further weight to the argument. Howell’s research, which includes lab trials, shows that the capillary action theory often doesn’t hold up in real-world conditions. “If you build a brick pillar and stand it in a tray of water, the bricks in the water will get wet, but the water doesn’t rise by capillary action,” Howell explains. Most modern materials—such as cement-based and lime mortars—are far less porous, preventing water from travelling through them.

The Chemical Damp-Proofing Industry

This brings us to the lucrative chemical damp-proofing industry. Companies that specialise in rising damp often recommend injecting a new chemical DPC into a property to “fix” the problem. The reality is that these chemical treatments don’t always address the root cause of the damp—and sometimes, they can even make the problem worse.

Rather than solving the issue, these treatments can mask underlying problems like moisture penetration or condensation, which are more likely to be the true causes of damp in your home. And, as Boniface points out, these treatments are not only ineffective—they are often expensive and unnecessary.

So, What Causes Damp?

If rising damp is rarely the culprit, what’s really behind damp issues in buildings?

According to experts, the primary causes are moisture penetration and condensation:

1. Moisture Penetration: This occurs when rainwater or groundwater seeps into the property through cracks in the walls or inadequate roofing. It’s a more common issue in properties where the exterior is compromised or where guttering and drainage systems are failing.
2. Condensation: The most frequent cause of damp in homes today is condensation. When warm, moist air inside the building meets cooler surfaces (like windows, walls, or floors), it condenses and creates damp patches. This is especially common in areas with poor ventilation or where there’s a significant difference between indoor and outdoor temperatures.

Why You Might Not Need a New DPC

Most buildings built after the 20th century already have a damp-proof course in place. Traditional DPCs were made from slate, a material that has been used for thousands of years for its impermeability. So, if your property was built with a solid slate DPC, there’s no reason to believe rising damp is a problem, unless there’s been a structural failure of some kind.

That’s why here at Alpine Surveys, we always recommend having an independent, expert survey conducted before making any decisions about damp-proofing treatments. We are committed to providing honest, accurate assessments of damp in your property.

Conclusion: Know the Truth About Damp

Rising damp is an issue that’s been heavily marketed by damp-proofing companies, but it’s not nearly as common as many people believe. While some damp problems are real, they are typically the result of condensation or moisture penetration rather than rising damp. Before investing in expensive and potentially ineffective chemical treatments, it’s important to get an accurate diagnosis from a professional.

If you suspect damp in your property, don’t rely on one-size-fits-all solutions. Get in touch with Alpine Surveys for an independent, expert assessment. We’re here to help you understand what’s really going on with your property—and what you can do to fix it.