What They Don’t Tell You About Cavity Wall Insulation

Cavity wall insulation has long been marketed as the key to improving energy efficiency in homes, reducing heat loss, and slashing heating bills. While it’s true that cavity wall insulation can have significant benefits, there are also several dangers of cavity wall insulation. These hidden downsides can cause serious issues in your home, and if left unchecked, they could lead to costly repairs and health risks.

The Purpose and Appeal of Cavity Wall Insulation

Cavity wall insulation was introduced as a response to the energy crises of the 1970s and the growing emphasis on energy conservation. The basic idea is simple: by filling the gap (or cavity) between the external and internal walls of a building with an insulating material, you can prevent heat from escaping your home, keeping it warmer in the winter and cooler in the summer.

In theory, this sounds perfect; less heat loss means less energy used for heating, which then means lower energy bills. Governments and energy companies have heavily promoted cavity wall insulation over the years, often offering grants and incentives to encourage homeowners to adopt this energy-saving measure. But what they don’t tell you is that cavity wall insulation isn’t always a perfect solution. In fact, in some cases, it can do more harm than good.

The Hidden Dangers of Cavity Wall Insulation

1. Dampness and Mould Growth

   One of the most significant risks associated with cavity wall insulation is the potential for dampness and mould. The purpose of the cavity between your walls is to prevent moisture from penetrating the inner walls of your home. However, when this cavity is filled with insulation material, it can disrupt the natural flow of moisture.

   If the insulation becomes damp, either from rain, rising damp, or condensation, it can trap moisture within the walls. Unlike open cavities, which allow moisture to evaporate, insulated cavities can hold onto water, or the insulation material itself can’t dry out, leading to persistent dampness. This dampness can present itself in different ways, such as patches on your walls, peeling wallpaper, or even black mould, which can pose serious health risks.

   

2. Why Does This Happen?

    

   • Poor Installation: If the insulation is not installed correctly, gaps or bridges can form, allowing water to seep into the insulation material.
   • Inappropriate Materials: Not all insulation materials are suitable for all types of walls. Using the wrong type of insulation can exacerbate moisture issues.
   • Climate and Location: Homes in areas with high rainfall or poor drainage are particularly at risk, as the walls are more likely to be exposed to moisture. As you can imagine, this is particularly problematic in the rainy UK!
3. Reduced Insulation Effectiveness

   When insulation becomes wet, it loses much of its insulating ability. Wet insulation can actually make your home colder because it allows heat to escape more easily. This can lead to higher heating bills—the very thing cavity wall insulation was supposed to prevent.

4. Structural Damage
5. Over time, trapped moisture can cause serious structural problems. Damp walls can weaken plaster and cause wooden elements, such as joists and beams, to rot. In extreme cases, it can even compromise the structural integrity of your home, leading to expensive and extensive repairs. In steel or wood framed homes, cavity wall insulation poses a real threat to the structural integrity and safety of the property.
6. Misdiagnosed Damp and Mould Issues

   One of the most frustrating aspects for homeowners is the difficulty in diagnosing the true cause of damp and mould problems. Many homeowners spend thousands of pounds on various treatments and repairs, only to find that the real culprit, damp cavity wall insulation, was overlooked.

   Common damp misdiagnosis include:

   • Rising Damp: Some might believe rising damp is to blame when, in reality, the moisture is trapped in the walls due to the insulation.
   • Poor Ventilation: Another common assumption is that lack of ventilation is causing condensation and mould, when the real issue is within the walls.

What to Do If You Suspect Cavity Wall Insulation is Causing Problems

If you can’t pinpoint the source of damp or mould in your home, it may be due to your cavity wall insulation. Here’s what you should do:

• Contact CavClear for a damp survey: Our qualified surveyors will assess the condition of your walls and find the root cause of your damp, which may be insulation.
• Consider Removal: In cases where there is damp cavity wall insulation, removing the insulation might be the best option to prevent further damage.
• Fix External Issues: Ensure your home’s external walls are in good condition. Repair any cracks, damaged pointing, or faulty gutters that could allow water to penetrate.
• Improving Ventilation: While not a solution to damp insulation, improving your home’s ventilation can help reduce the impact of any dampness by promoting air circulation.

These are all services offered by us! You can reach out to us here. If you suspect the dangers of cavity wall insulation are present in your home or you can’t identify the cause of the damp issues, it’s time to reach out to us. It’s better to address these issues sooner rather than later to protect both your homes safety and stability, as well as the health of those living in the property who could be at risk due to damp and mould.