Approved Cavity Wall Insulation Installers

What is Cavity Wall Insulation?

Cavity wall insulation involves insulating the gap between a building’s inner and outer walls. The outer cavity wall is typically constructed with brick, while the inner wall may consist of concrete, structural clay, or brick. This method differs from solid stone walls, where there is no space between the inner and outer layers internal wall insulation is more suitable.

Cavity wall insulation is commonly applied in residences featuring cavity walls, comprised of two layers of brick or block with a gap between them. Its purpose is to reduce heat loss, improve energy efficiency, and decrease heating costs.

According to the Energy Savings Trust, approximately 33% of heat is lost through cavity walls. When suitable, cavity wall insulation is among the most efficient forms of home insulation, often paired with loft insulation.

Professional installation is crucial. Here are key factors an installer should evaluate to ascertain if cavity wall insulation suits your home:

Shown are the different types of wall suitable for either cavity wall or internal wall insulation. 

How does Cavity Wall Insulation Work?

Cavity wall insulation is a process that entails filling the space between the inner and outer walls of a building with insulation material to minimise heat loss and boost energy efficiency. Here’s a breakdown of the typical procedure:

Cavity Wall Construction: Cavity walls consist of two layers of brick or block with a gap or cavity in between, which allows for insulation while providing moisture protection.

Insulation Material Selection: Common materials used include mineral wool (such as glass wool or rock wool) or polystyrene beads known as cavity wall beads.

Drilling Holes: Small holes are drilled into the external wall at regular intervals to inject the insulation material.

Injection of Insulation Material: The chosen material is injected into the cavity through the drilled holes, expanding or filling the space.

Sealing of Holes: Once the cavity is filled, the drilled holes are sealed with mortar to maintain the exterior wall’s appearance.

Inspection and Quality Control: A professional may inspect the installation to ensure even coverage and the absence of gaps or voids.

Key Benefits

  • Thermal Barrier: Insulation reduces heat transfer through walls, enhancing interior comfort.
  • Energy Efficiency: Cavity wall insulation reduces the need for heating or cooling, potentially leading to energy savings.
  • Condensation Control: Helps prevent dampness and mold by regulating interior moisture levels.

It’s crucial to evaluate a building’s suitability for cavity wall insulation and ensure compliance with building regulations and standards during material selection and installation.

Diagram showing how cavity wall insulation works

Benefits Of Cavity Wall Insulation

Cavity wall insulation provides numerous benefits for homeowners, including enhanced energy efficiency, improved comfort, and potential cost savings. Here are some key advantages of cavity wall insulation:

Cavity wall insulation acts as a thermal barrier, reducing the transfer of heat through the walls. This helps to retain warmth in the winter, leading to a more energy-efficient home.

By reducing heat loss, cavity wall insulation can result in lower heating bills. A well-insulated home requires less energy to maintain a comfortable temperature.

Insulated walls help maintain more stable indoor temperatures. This means warmer interiors in the winter and cooler interiors in the summer.

Cavity wall insulation is often a quick and straightforward installation process that can be completed in a day. This minimises disruption to occupants.

A more energy efficient home results in lower carbon emissions. By reducing the need for heating, cavity wall insulation contributes to environmental sustainability.

Improving the energy performance of a property through insulation measures can enhance its market value. Many homebuyers appreciate energy efficient features.

In Scotland Government grants are available to encourage homeowners to install cavity wall insulation. These financial incentives will offset your installation costs.

Cavity wall insulation, when installed correctly, can be a long-lasting solution. It requires minimal maintenance and continues to provide benefits over the long term.

In addition to thermal benefits, cavity wall insulation can contribute to sound insulation. It helps reduce the transmission of external noise into the home, creating a quieter living environment.

Before proceeding with cavity wall insulation, we recommend consulting with our partner insulation installers to evaluate your property's suitability and to explore available grants.
Insulation Scotland


Professional installation is essential for effective cavity wall insulation. Trained professionals should handle the installation to ensure even coverage and prevent issues like thermal bridging.

Before proceeding with cavity wall insulation, it’s crucial to assess the suitability of the property. Not all buildings are suitable for this type of insulation, so a professional assessment is necessary.

Installation should adhere to relevant building regulations and standards to ensure safety and performance. Compliance with these regulations is essential for the success of the insulation project.

Best Material For Cavity Wall Insulation

The selection of cavity wall insulation material hinges on diverse factors, encompassing building specifications, climate, and individual preferences. Here are some prevalent types of cavity wall insulation materials:

Mineral Wool (Glass Wool or Rock Wool)


Exhibits commendable thermal insulation properties.

Non-combustible and endowed with fire-resistant attributes.

Shows resilience against moisture absorption.

Offers potential for sound insulation.


Mandates professional installation to ensure uniform coverage.

Foam Insulation (Polyurethane or Polystyrene):


Boasts high thermal insulation capabilities.

Lightweight and facilitates easy installation.

Demonstrates resistance to moisture.

Renders a seamless and airtight seal.


Certain foams may emit gases during installation, necessitating proper ventilation.

Initial cost might be higher.

Cellulose Insulation


Crafted from recycled paper, rendering it environmentally friendly.

Effective thermal insulation performance.

Can be injected into the cavity.


May necessitate additives to enhance fire resistance.

Moisture resistance levels can vary.

Cavity Bead Insulation (Expanded Polystyrene Beads)


Lightweight and facilitates straightforward installation.

Possesses commendable thermal insulation properties.

Shows resistance to moisture.


Requires professional installation.

May experience settling over time, potentially affecting performance.

Cavity insulation beads are generally the best type of material to install.

Diagram shown external and internal walls with the cavity wall insulation beads installed in-between

Problems Due To Poor Installation

There has been some news articles including this one East Kilbride near Glasgow documenting problems with cavity wall insulation due to instances of poor installation, problems like dampness and moisture have been reported. However, we assure you that our partner installers have a track record of successful installations spanning thousands of projects over the years. Installing cavity wall insulation involves several steps, and it’s crucial to have experienced installers who are well versed in the process to prevent potential issues.

One common issue is thermal bridging, which occurs when there’s a break in the insulation layer, allowing heat to bypass the insulating material through a direct pathway.

Potential Consequences of Thermal Bridging:

Reduced Energy Efficiency:

Thermal bridging can compromise the overall energy efficiency of the building, leading to increased heat loss and higher energy bills.

Cold Spots and Condensation:

Areas with thermal bridging may become cold spots on the internal walls, potentially leading to issues like condensation and dampness. This can impact occupant comfort and indoor air quality.

Mould Growth:

Cold spots and condensation can create conditions favourable for mould growth, posing health risks and requiring additional remediation measures.

There are other issues with installing cavity wall insulation on listed buildings, it can be a complex issue, and there are specific considerations and regulations that must be followed due to the historic and protected nature of these premises. Listed buildings are those officially recognised and protected for their special architectural or historic interest.

If you are put off cavity wall insulation, you can consider other options such as internal wall insulation and loft insulation

Damp and aged cavity wall insulation removal

Cavity Wall Insulation Removal and Replacement

If you have had an installation completed that has had some of issues highlight above, you can have cavity wall insulation removal and replacement carried out to solve the problem. This is also referred to as cavity wall extraction and refill.

Sometimes people have cavity wall removed and replaced not because of any of the highlighted issues or any major problems, simply due to it being aged. If your cavity wall was insulated around 15  to 20 years ago, it will have older less effective materials that are not as efficient as what is available today.

Here’s more information about the extraction and refill process:

The Extraction Process

Assessment: A professional assessment is conducted to determine the condition of the existing insulation and identify any issues that need to be addressed.

Extraction: Specialised equipment, such as cavity wall extraction machines, is used to remove the old insulation material from the wall cavities. This process typically involves drilling small holes in the walls to access the cavities without causing damage to the structure.

Thoroughness: Great care should be taken to ensure that all old insulation material is completely removed from the cavities to prepare them for the refill process.

The Refill Process

Selection of Insulation Material: Based on factors such as building requirements, climate, and energy efficiency goals, a suitable insulation material is chosen for the refill. Common options include mineral wool, foam insulation, or cellulose insulation.

New Installation: The new selected insulation material is injected or blown into the wall cavities using specialised equipment. Care is taken to ensure that the cavities are completely filled and that the insulation forms a continuous barrier.

Quality Assurance: After the refill process is complete, a thorough inspection is conducted to verify that the insulation has been installed correctly and that the cavities are properly filled.

Benefits of Extraction and Refill

Improved Energy Efficiency: New insulation materials can enhance the thermal performance of the building, reducing heat loss and energy consumption by up to 33 percent.

Enhanced Comfort: Properly insulated walls help maintain more consistent indoor temperatures and reduce drafts, resulting in increased comfort for occupants.

Moisture Management: Upgrading insulation can help mitigate moisture problems and improve the overall indoor air quality.

Long Term Savings: Investing in efficient insulation can lead to lower energy bills and potentially increase the value of the property.

Cavity wall insulation removal and replacement can be a cost effective as in most cases you will qualify for a government grant and it is one of the most efficient ways to upgrade the thermal performance of your building, leading to improved comfort, energy savings, and environmental sustainability.

Professional cavity wall insulation removal and replacement
Insulation Scotland

Cavity Wall Insulation Installers Glasgow

Our insulation installer partners are highly experienced in cavity wall insulation, with thousands of successful installations under their belt. They ensure that your project follows a meticulous process to completion.

Moreover, we’re ready to explore alternative options if cavity wall insulation isn’t suitable for your home. Rest assured, all our partnered installers are fully accredited, including TrustMark approval, enabling them to carry out installations eligible for government grant schemes.

Cavity Wall Insulation Grant Glasgow

Cavity wall insulation is in high demand across Scotland, making it a key focus for government grant support covering installation costs. As well as cavity wall insulation grants, customers frequently seek grants for loft insulation, grants are allocated based on eligibility and the potential improvement to your home’s EPC rating. Several insulation grants are accessible, such as the widely utilised Home Energy Scotland grant and loan scheme, the ECO 4 scheme, and the Great British Insulation scheme. Our partners at Insulation Scotland are available to assist with your application process and will proceed with cavity wall insulation installation if you secure funding.

For additional details and to discuss if you qualify for a grant, please call us or complete our short contact form.

Insulation Scotland

Glasgow Cavity Wall Insulation Installers

Get A Cavity Wall Insulation Quote

Please fill out the contact form below so we can arrange a no obligation internal wall insulation survey. Please allow up to 48 hours for one of our representatives to contact you to discuss on the telephone.

Instant Quote in Glasgow

Please call us to discuss your requirements, if you have pictures of your walls, loft, roof or home layout please provide these to speed up the process.

Cavity Wall Insulation Across Scotland

Our team of insulation contractors and surveyors travel all over Scotland providing cavity wall insulation in Aberdeenshire, Angus, Argyll & Bute, Ayrshire, Clackmannanshire, Dumfries and Galloway, Dundee, East Ayrshire, East Dunbartonshire, East Lothian, Edinburgh, Glasgow, Falkirk, Fife, Highland, Inverclyde, Inverness, Midlothian, Moray, North Ayrshire, North Lanarkshire, Perth and Kinross, Renfrewshire, Stirling, South Ayrshire, South Lanarkshire, The Borders, West Dunbartonshire and West Lothian. 

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