Approved Cavity Wall Insulation Installers

What is Cavity Wall Insulation?

Cavity wall insulation is the method of insulating the space between the inner and outer walls of a building with outer cavity wall generally made of brick and inner wall comprising of concrete, structural clay or also brick, unlike solid stone walls where internal wall insulation is more suitable.

Cavity wall insulation is typically installed in homes with cavity walls, which feature two layers of brick or block separated by a gap, this insulation aims to minimise heat loss, enhance energy efficiency, and lower heating expenses.

According the Energy Savings Trust around 33% of heat is lost through cavity walls, if your homes walls are suitable it is one of the most effective types of home insulation you can install alongside loft insulation. 

Professional installation is paramount, below are some of the things an installer should assess to determine if cavity wall insulation is best for 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 involves filling the gap between the inner and outer walls of a building with an insulating material to minimise heat loss and enhance energy efficiency. Here’s an overview of how the process typically works:

Cavity Wall Construction

Cavity walls consist of two layers of brick or block separated by a gap or cavity. This gap allows for the installation of insulation while providing moisture protection.

Insulation Material Selection

Common materials 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 selected 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 colour matched mortar to maintain the exterior wall’s appearance.

Inspection and Quality Control

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

Key Benefits

Thermal Barrier: Insulation reduces heat transfer through walls, improving interior comfort.

Energy Efficiency: Cavity wall insulation reduces the need for heating or cooling, leading to potential energy savings.

Condensation Control: Helps prevent dampness and mould by controlling interior moisture levels.

It’s essential to assess 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 offers several benefits for homeowners, contributing to increased 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 considering cavity wall insulation, it's advisable to consult with our partner insulation installers to assess the suitability of your property, and explore available grants. Each home is unique, and the benefits can vary based on factors such as the existing insulation, climate, and energy usage patterns.
Insulation Scotland


  • Professional Installation: Proper installation is crucial for the effectiveness of cavity wall insulation. It should be carried out by trained professionals to ensure even coverage and avoid issues such as thermal bridging.

  • Suitability: Not all buildings are suitable for cavity wall insulation. A professional assessment should be conducted to determine the suitability of the property.

  • Compliance with Regulations: Installation should comply with relevant building regulations and standards to ensure safety and performance.

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 in Scotland documenting problems with cavity wall insulation due to poor installation, issues including reports of dampness and moisture. We can assure you that our partner installers will ensure your installation is done correctly with thousands of successful jobs being completed over the years. There are a lot of steps to follow when installing cavity wall insulation, so it’s important to have installers well versed in fitting it who will understand and avoid any of the issues below arising.

Some issues are caused by thermal bridging which occurs when there is a break in the insulation layer, allowing a direct pathway for heat to bypass the insulating material. 

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

History Of Cavity Wall Insulation in Scotland

The history of cavity wall insulation in Scotland reflects broader trends in building practices and energy efficiency awareness. Here’s a detailed overview:

Early Developments

  • Pre-20th Century: Most buildings were constructed with solid walls, and the concept of cavity walls was not yet introduced. Buildings relied on thick stone or brick walls for insulation, which were not very effective in retaining heat.
  • 1920s-1930s: Cavity wall construction began to be adopted in Scotland, following trends in other parts of the UK. These walls consisted of two layers of brick with a gap (cavity) in between to prevent water penetration and improve thermal performance.

Mid-20th Century

  • 1940s-1950s: Post-World War II building booms saw more widespread use of cavity walls. Initially, the cavities were left empty, but the potential for improved thermal performance through insulation began to be recognized.
  • 1960s: Early attempts at cavity wall insulation started. Materials such as expanded polystyrene beads and mineral wool were experimented with, but the practice was not yet common.


  • Energy Crisis of the 1970s: The oil crisis led to increased awareness of energy efficiency. Insulating buildings became a priority to reduce heating costs. Government incentives and programs began to promote cavity wall insulation.
  • 1980s: More systematic approaches to cavity wall insulation were developed. The use of urea-formaldehyde foam became popular, although it later fell out of favor due to health concerns and issues with degradation over time.


  • Regulatory Changes: Building regulations started to mandate better energy efficiency standards, leading to more consistent use of cavity wall insulation in new constructions.
  • Technological Advancements: Improved materials like polyurethane foam, and blown mineral wool became standard, offering better thermal performance and durability.


  • Government Programs: Initiatives like the Energy Efficiency Commitment (EEC) and later the Carbon Emissions Reduction Target (CERT) incentivized homeowners to install cavity wall insulation.
  • Retrofitting Existing Buildings: Many older buildings were retrofitted with cavity wall insulation as part of energy efficiency upgrades. Techniques for safely insulating older cavity walls were refined.

2010s to Present

  • Enhanced Standards: Modern building regulations in Scotland now require high standards of thermal insulation, making cavity wall insulation a standard practice in new builds.
  • Sustainability Focus: There is an increased emphasis on using environmentally friendly insulation materials, and efforts continue to improve the energy efficiency of the existing housing stock through government-backed programs.
  • Quality Control: Certification schemes and quality assurance processes have been established to ensure proper installation and performance of cavity wall insulation.

Current Trends in 2024

  • Energy Efficiency and Climate Goals: Scotland’s commitment to reducing carbon emissions and improving energy efficiency in buildings remains strong. Cavity wall insulation continues to be a key measure in achieving these goals.
  • Technological Innovations: Ongoing research and development are leading to better insulation materials and installation techniques, ensuring even greater energy efficiency and longevity.

In summary, cavity wall insulation in Scotland has evolved from early experimental stages to a well-established and regulated practice, driven by the need for energy efficiency and improved building standards.

Insulation Scotland

Cavity Wall Insulation Installers Scotland

As stated our insulation installers partners are well versed in installing cavity wall insulation, they have thousands of installs completed successfully and will ensure your project is completed following the same process.

We can also discuss and provide the best alternative options for your home or if cavity wall insulation is not suitable. 

All of the installers we work with are fully approved with the likes of TrustMark meaning they are able to install insulation where funding is awarded via government grant schemes. 

Cavity Wall Insulation Grant Scotland

Cavity wall insulation and loft insulation are the most prevalent forms of home insulation in Scotland in terms of demand, hence it is heavily supported by government grants to cover the installation cost. As well as grants for cavity wall insulation, customers frequently seek grants for loft insulation, funding is awarded in relation to eligibility and what will enhance your home’s EPC rating more.

There are various insulation grants available including popular Home Energy Scotland grant and loan scheme, the ECO 4 scheme and the Great British Insulation scheme.

Insulation Scotland’s partners are on hand to aid you in your application process and will also subsequently install your cavity wall insulation 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.

ECO Flex Cavity Wall Insulation Grant

The ECO flex or local authority flex stands as an additional grant option for cavity wall insulation. This particular grant is limited to the North Lanarkshire, South Lanarkshire, and Renfrewshire council areas, where our endorsed partners serve as approved installers.

ECO flex extends financial support to individuals not receiving benefits but earning less than £31,000. Eligibility criteria include having a home EPC rating below D and meeting other specified conditions.

For more information on all of the government grants available for home insulation, visit our insulation grants Scotland page.

Facts On Scotland

We have partner installers all over Scotland, here are some interesting facts about our great nation:

  1. Population: Official statistics project that Scotland’s population will increase from 5.35 million in 2014 to 5.51 million by 2024, and further to 5.7 million by 2039.
  2. Biggest Cities: According to Wikipedia the biggest cities in Scotland by population are Glasgow – 632,350. Edinburgh – 506,520 and Aberdeen – 198,590.
  3. There are many famous Scots, some of the most notable include Alexander Graham Bell, John Logie Baird, Mary, Queen of Scots and William Wallace.
  4. Scotland, and in particular Glasgow played a huge role in the Industrial Revolution, the city diversified into heavy industries like shipbuilding, locomotive construction and other heavy engineering that could thrive on nearby supplies of coal and iron ore. Between 1870 and 1914, Glasgow ranked was one of the richest and finest cities in Europe.
  5. The famous Edinburgh festival is the largest arts festival in the world showcasing up and coming acts for arts, drama, live music and especially comedy, having helped many successful artists launch their careers.
Insulation Scotland

Cavity Wall Insulation Installers With A Proven Track Record!

Get A Cavity Wall Insulation Quote

Please complete the contact form provided below to schedule a no-obligation cavity wall insulation survey and to discuss government grants you may qualify for.

Please anticipate a response from one of our representatives within 48 hours to discuss your requirements further over the phone.

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