What are the Disadvantages of Cavity Wall Insulation?

Matt Keane
November 14, 2023

Cavity wall insulation is a popular method for improving home energy efficiency, but it has some drawbacks. While it offers significant benefits like reduced energy bills and a warmer living space, there are potential disadvantages that homeowners should be aware of.

In this blog, we're going to take a closer look at the less-talked-about side of cavity wall insulation. Whether you're considering insulating your home or already have cavity wall insulation installed, it's important to understand the full picture.

From issues with dampness to the complexities of installation, we'll cover the key challenges and concerns associated with this insulation method. Our aim is to provide you with a balanced view, helping you make an informed decision about cavity wall insulation for your home.

Want to know more? So, let's dive right into it!

Understanding Cavity Wall Insulation

Cavity wall insulation refers to the process of filling the gap or cavity between the inner and outer walls of a building with insulating material in order to improve energy efficiency.

Definition Of Cavity Wall Insulation

Cavity wall insulation is a way to keep your home warm. It fills the space in between two brick layers of your house's walls. This layer blocks heat from leaving the house and cold air from coming in.

In fact, the most common types are made out of wool or foam. Yet, this type of insulation may not work well with every home's design or structure. Sometimes, if it is not done right, it can cause problems like gaps and cracks or let dampness into your home, which can lead to mould growth.

Also, setting up cavity wall insulation needs skill and money, so that might be hard for some people too.

Types of Cavity Wall Insulation

Let's talk about the different types of cavity-wall insulation that homeowners can choose from. There are a few options available, each with its own advantages and disadvantages. One common type is fluffy insulation, which is made from materials like mineral wool or glass fibres.

Another option is rigid foam insulation, which provides good thermal resistance and can help prevent heat loss. Spray foam insulation is another popular choice, as it expands to fill gaps and cracks in the walls, providing excellent coverage.

In short, it's important to consider factors such as cost, effectiveness, and suitability for your home when choosing the right type of cavity wall insulation.

Potential Problems With Cavity Wall Insulation

The installation of cavity wall insulation can lead to potential problems such as poorly fitted insulation causing gaps and voids, issues with EPS beads and wall tie corrosion, dampness, and mould growth, as well as difficulties in fixing damages.

Poorly Fitted Insulation Leads To Gaps And Voids

Sometimes, cavity wall insulation can be installed poorly, and this can cause problems. When the insulation is not fitted properly, it can create gaps and voids in the walls. This means that some areas of the cavity may not have any insulation at all, which reduces its effectiveness.

Additionally, these gaps and voids can allow air to circulate within the walls, leading to heat loss and a decrease in energy efficiency. It's important to make sure that the installation is done correctly to avoid these issues.

Issues With EPS Beads And Wall Tie Corrosion

We need to be aware of two specific issues when it comes to cavity wall insulation: EPS beads and wall tie corrosion. EPS beads, or expanded polystyrene beads, are commonly used in cavity wall insulation.

However, there have been cases where these beads have escaped from the walls, causing problems. Additionally, there can be an issue with wall tie corrosion when metal ties used to hold the inner and outer walls together start rusting due to moisture trapped in the cavity.

Furthermore, these issues highlight the importance of proper installation and monitoring to ensure that the insulation performs as intended without any complications.

Dampness And Mould Growth

One important thing to consider when it comes to cavity wall insulation is the potential for dampness and mould growth. This occurs because if the insulation is not properly installed, it can create pockets of trapped moisture within the walls and loft space.

This excess moisture can lead to the growth of mould, which can be harmful to both your health and the structural integrity of your home. It's essential to make sure that any cavity wall insulation is fitted correctly and has adequate measures in place to prevent dampness and mould from becoming an issue.

Additionally, some types of insulation materials may be more prone to absorbing moisture than others. For example, certain fluffy insulations, like shredded recycled paper, can clump together when damp, reducing their effectiveness at providing thermal insulation.

Even more, this clumping can also create areas where mould can grow more easily. It's important during installation to ensure that these materials are adequately protected against moisture absorption.

To address this concern, homeowners should choose a reputable installer who is experienced with proper installation techniques and who uses high-quality insulation materials that are specifically designed for cavity walls.

Therefore, regular inspections after installation will also help identify any potential issues early on so they can be promptly addressed.

Difficulty In Fixing Damages

Fixing damage to cavity wall insulation can be a challenge. If there are issues with the insulation, such as clumping or dampness, it may not be easy to remove and replace. This can be a disadvantage for homeowners who want to make changes or repairs in the future.

As well, some types of cavity wall insulation, like mineral wool, can be messy and difficult to clean up if they become damaged. It's important to carefully consider the potential difficulties in fixing any damages before deciding on cavity wall insulation for your home.

Alternatives to Retrofit Cavity Wall Insulation

  • Spray foam insulation provides a seamless and airtight solution, preventing the formation of gaps or voids that can occur with cavity wall insulation. It also offers superior thermal performance and moisture prevention.
  • Rigid foam insulation is another popular alternative, providing excellent thermal resistance and moisture protection. It can be installed on both the interior and exterior of the walls, offering flexibility in terms of application.
  • Exterior wall insulation involves adding an insulating layer to the outside of the building, reducing heat loss through the walls while also improving its aesthetic appeal. This method eliminates any potential damage or issues with existing cavity wall insulation.
  • Internal wall insulation is done by attaching insulating boards to the inside surface of external walls. While it can be more disruptive during installation, it allows homeowners to retain their existing cavity wall insulation if desired.

These alternatives offer effective solutions for homeowners looking to improve energy efficiency without facing potential problems associated with retrofitting cavity wall insulation.

Learn more about these options in detail by following below.

Spray Foam Insulation

Spray foam insulation is another alternative to retrofit cavity wall insulation. It involves spraying liquid foam into the cavity, which then expands and hardens to provide insulation.

One advantage of spray foam insulation is that it can fill gaps and voids more effectively than other types of insulation, reducing the risk of heat loss. It also provides a barrier against moisture, helping to prevent dampness and mould growth in the walls.

However, it's important to note that spray foam insulation can be more expensive than other options, so homeowners on a tight budget may need to consider this factor before making a decision.

Rigid Foam Insulation

Rigid foam insulation is another alternative to consider for cavity wall insulation. This type of insulation is made from solid boards or panels that are designed to fit snugly between the walls.

Rigid foam insulation provides excellent thermal insulation and can help reduce heat loss in your home. It also has good moisture resistance, which can help prevent dampness and mould growth.

One advantage of rigid foam insulation is that it is easy to install and doesn't require any special skills or expertise. However, it's important to note that rigid foam insulation may not provide as much soundproofing compared to other types of insulation.

So, if you're someone who's sensitive to noise, this might be a drawback worth considering.

Exterior wall insulation

Exterior wall insulation is an alternative to cavity wall insulation that can help improve the energy efficiency of your home. It involves adding a layer of insulation material, such as rigid foam boards, to the outside walls of your house.

This helps prevent heat from escaping and keeps your home warmer in winter and cooler in summer. Exterior wall insulation can also help reduce noise transmission from outside and protect the external walls against weather damage.

It's important to note that exterior wall insulation may require professional installation and could be more expensive than other options. However, it offers advantages such as improved thermal performance and aesthetic enhancements for your home's exterior.

Internal Wall Insulation

Internal wall insulation is a method of insulating the walls inside your home to improve energy efficiency and comfort. It involves adding insulation material to the internal surfaces of external walls.

By doing this, you can reduce heat loss through the walls and make your home warmer and more comfortable. Internal wall insulation can also help reduce your heating bills by keeping more heat inside your home.

It's important to note that this type of insulation may be more suitable for solid brick or stone walls than cavity walls. Additionally, it's important to consider any potential impact on room sizes and aesthetics before deciding on internal wall insulation as an option for improving energy efficiency in your home.

To Sum Up

There are several potential disadvantages to cavity wall insulation. It can cause dampness and moisture problems, be expensive to install, and may not provide effective insulation for all homes.

Additionally, if installed incorrectly or with the wrong materials, it may not deliver the desired thermal benefits. Therefore, homeowners should carefully consider these drawbacks before opting for cavity wall insulation.

However, for expert guidance and quality installation, consider reaching out to Build Pro to ensure your insulation is done right.

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*FYI, parts of this blog post were drafted by artificial technlogy. But rest assured, it's been thoroughly researched, edited, reviewed and me & my team.

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