Does Your Project Require Rendering & Insulation?

Cavity Wall Insulation Cost Guide

Are you wondering how much cavity wall insulation cost? The average cost of cavity wall insulation is around £500, and the job typically takes between 4-8 hours. However, these are rough estimates and there are several factors to consider.

In this comprehensive cost guide, you’ll find a breakdown of pricing information based on house sizes and other factors. You’ll also learn how long the job should take and a general overview of what will be involved.

Additionally, you’ll discover how to find and hire an insulation contractor, as well as costs for different types of cavity insulation like cavity wall insulation injection.

Cavity wall insulation cost
Source: Self-build

Average Cost of Cavity Wall Insulation

The cost of cavity wall insulation varies depending on several factors, such as the type of property, the size of the property, and the insulation material used. On average, the cost of cavity wall insulation in the UK ranges from £500 to £1,500.

The following table provides an estimate of the average cost of cavity wall insulation per square meter for different types of properties:

Property TypeAverage Cost per Square Meter
Detached House£20 – £35
Semi-Detached House£15 – £30
Mid-Terrace House£10 – £25
End-Terrace House£15 – £30
Bungalow£20 – £30

It is important to note that these are rough estimates and the actual cost may vary depending on the specific requirements of the property. Additionally, it is important to choose a reputable and qualified installer to ensure the insulation is installed correctly and to a high standard.

Cavity wall insulation can be a cost-effective way to improve the energy efficiency of a property and reduce heating bills. It is recommended to get quotes from multiple installers and compare the prices and services offered before making a decision.

How Much Does Cavity Wall Insulation Cost?

The cost of cavity wall insulation varies depending on the type of insulation chosen and the area to be filled. The cost is primarily determined by the size of the home. For instance, a mid-terrace home can cost between £300-£600, while a semi-detached house can cost between £600-£800. A large detached home could cost around £800-£1,200.

If you have a fixed budget, you may want to consider cavity wall insulation grants. These grants are available to some homeowners through energy suppliers. They can cover some or all of the cost of cavity wall insulation.

The benefits of cavity wall insulation include increased energy efficiency and a more balanced temperature throughout the home. It can also help to reduce heating energy consumption. It is worth noting that the savings made on heating bills will pay for the insulation quickly.

The following table shows the average cost of cavity wall insulation, assuming that there is no insulation to be removed and that the job is uncomplicated:

House TypeAverage Cost
Mid Floor Flat£300-£500
Detached Bungalow£450-£650
Terraced£350-£550
Semi-detached£500-£700
Detached£700-£1,000

It is important to note that these prices are averages and that the actual cost may vary depending on the specific circumstances of the home.

Wall Cavity Insulation Prices

Cavity wall insulation is a cost-effective way to improve the energy efficiency of a home. The cost of cavity wall insulation depends on various factors such as the size of the property, the type of insulation material used, and the installation costs.

The average cost of cavity wall insulation in the UK is between £475 and £800. However, the cost can vary depending on the size of the property. For instance, a small flat may cost around £350, while a larger detached house may cost up to £1,500.

It’s important to note that the cost of cavity wall insulation can be affected by various factors such as the type of insulation material used, the installation costs, and the size of the property. Therefore, it’s recommended to get quotes from multiple providers before deciding on the best option.

Labour Costs and Timescales

The duration and average cost for labour to install insulation varies based on the house type. Here is a breakdown of the estimated timescales and costs for different house types:

House TypeDurationAverage Cost
Mid Floor Flat1-2 hours£100-£200
Terraced2-3 hours£200-£350
Semi-detached2-3 hours£300-£450
Detached Bungalow3-4 hours£400-£550
Detached3-4 hours£500-£650

Labour costs and timescales are important factors to consider when planning insulation installation. It is important to note that these estimates are just that, and actual costs and timescales may vary based on individual circumstances.

Supply Costs

The cost of insulation supply varies depending on the type of insulation, the area that needs to be covered, and the supplier chosen. Mineral fibre insulation costs an average of £14-£20 per m2, wool fibre insulation costs £25-£35 per m2, EPS insulation costs £18-£28 per m2, PUR foam insulation costs £22-£26 per m2, and cavity wall boards cost £15-£17 per m2.

Cavity Wall Survey Cost

To determine if cavity wall insulation is suitable for a property, a cavity wall survey is required. The cost of a cavity wall survey depends on various factors such as the size of the property, its location, and the complexity of the job.

The average cost of a cavity wall survey in the UK ranges from £150 to £300. However, our experts at ProGuard Exteriors offer a free survey if the homeowner decides to proceed with the insulation installation.

It is recommended to obtain multiple quotes from different companies to compare prices and ensure that the survey is being carried out by a qualified and accredited professional.

It is important to note that a cavity wall survey is essential before any insulation installation takes place to ensure that the property is suitable for the procedure and to avoid any potential issues.

Cost of Replacing Wall Ties

Wall ties are the components that connect the two brick layers of a cavity wall. If the wall ties fail, cracks may appear in the exterior wall’s mortar.

It is recommended to replace the wall ties before installing cavity wall insulation, as repairing them may damage the insulation and reduce its effectiveness. The cost of replacing wall ties ranges from £1,000 to £2,000.

It is important to note that the cost of replacing wall ties per wall tie is around £5 to £8, and the cost per square metre is approximately £30 to £50.

Hard to Treat Cavity

Installing cavity wall insulation can be more difficult in certain circumstances. For example, if there is already insulation in the walls, it may need to be removed or worked around.

Similarly, if there is debris in the cavity wall, it can complicate the installation process. The cost of cavity wall insulation can vary significantly depending on the complexity of the situation.

In some cases, it may only add £100 to the cost, while in others, it could cost up to £1,500.

Heat Loss Survey Cost

To improve home efficiency, homeowners may consider getting a heat loss survey, which uses thermal imaging cameras to detect heat loss areas.

The survey results can point to the best changes to make to improve home efficiency. The cost of these surveys varies depending on the level of scan required and the size of the property. The price usually starts at around £200.

Roof Insulation Cost

Insulating the roof is a simple way to reduce heat loss. The cost of roof insulation typically ranges from £450 to £800 depending on the roof’s size.

Loft Insulation Cost

Insulating your loft can save you up to £215 per year, making it a worthwhile investment. Using the same insulation type as for your cavity wall could result in a discount from your installer. Loft insulation typically costs between £400 – £800.

Cost of New Windows

If your windows are in poor condition, replacing them can prevent heat loss from a home. The average cost to fully replace all windows in a home is around £3,500 to £5,000.

New Exterior Door Cost

Replacing a front door can cost around £500 on average. Investing in high-quality doors not only enhances the security of your home but also prevents heat from escaping. A new exterior door is a worthwhile investment for any homeowner.

Draught Proofing Cost

Draught proofing is an inexpensive way to save on energy bills. It can be done as a DIY project or by hiring a professional for around £400 to draught proof the entire house.

Cost Factors of Cavity Wall Insulation

The cost of cavity wall insulation in the UK depends on two main factors. Firstly, the size of the area that needs filling, which means that the more external walls you have, the higher the cost will be. Secondly, the type of insulation you choose will also affect the final price. According to industry experts, the average cost of cavity wall insulation ranges from £15 to £30 per square metre.

The most expensive insulation options are PUR, which costs between £25 – £35 per m2, and Sheep’s Wool, which costs between £25 – £35 per m2. On the other hand, the cheapest options are Mineral Fibre, which costs between £14 – £18 per m2, and cavity wall boards, which cost between £15 – £20 per m2.

What’s Involved in Installing Cavity Wall Insulation?

Before installing cavity wall insulation, an installer will carry out a survey to check if the walls are suitable for insulation and if there is any existing insulation in place. They will also assess the condition of the brickwork and look for signs of damp.

The installation process involves drilling a series of small holes into the exterior of the property. A pump is used to blow the insulation material into these holes until the cavity is filled. The holes are then fixed and covered, and filled to match the exterior of the home as closely as possible.

After the installation, a guarantee for the work should be received in the mail. An inspector may also visit to ensure that the work was completed to a good standard.

It is important to note that the cost of cavity wall insulation depends on the size of the property, the accessibility of the walls, the type of insulation chosen, and the installer selected. It is recommended to use a registered installer to ensure the best results and to check if financial help is available to pay for the insulation.

What is Cavity Wall Insulation?

Cavity wall insulation is a method used to trap heat between the inner walls of a property, allowing it to flow into adjacent rooms and eliminating draughts. The cavity can be found between the outer and inner brick walls of a house, and insulation is installed there to improve energy efficiency and reduce heating costs.

Can I Install Cavity Wall Insulation Myself?

Cavity wall insulation should be installed by a registered installer, even if you are experienced in DIY. Building regulations require the work to be completed by a professional. It is not recommended to attempt this job yourself.

Can I Have Cavity Wall Insulation?

Before considering cavity wall insulation, it is important to determine if your home is suitable for it. This section will cover two main sub-sections that will help answer this question.

Do I Have A Cavity Wall?

The first step in determining if your home is suitable for cavity wall insulation is to find out if you have a cavity wall. Here are a few ways to identify if your home has a cavity wall:

  • Brick Patterns: Look at the way the bricks are laid on your home. If all of the bricks are laid lengthways, then you probably have a cavity. If the bricks alternate between being long side on and short side on, then there will be no cavity in your wall.
  • Age of Your House: Homes built after 1920 were almost always built using cavity walls. Homes built between 1920 and 1970 were built with cavity walls and no insulation. Homes constructed between 1970 and 1990 might have insulation. Homes built after 1990 should have cavity wall insulation.
  • Thickness of Your Walls: If you have a cavity wall, then there will be a considerable distance between the exterior wall and the interior surface. The best place to see this is in the windows. If the windowsill is very narrow, less than about 250mm, then you won’t have a cavity.

If you are uncertain, you can drill through the wall to be sure. You will be able to feel where if there is a cavity because the drill will go slack after the first course of bricks, and then pick up again when it meets the second course.

Is My Cavity Wall Suitable For Insulation?

Once you have identified whether or not you have a cavity wall, you will need to determine if it is suitable for insulation. Here are a few factors that affect this:

  • Size of Gap: The cavity between the walls must be big enough for the insulation to fit. The gap must be larger than 50mm. In older homes, this might not be the case. You can check by removing a brick and measuring the distance to the interior wall. Or you can drill a hole and measure from there.
  • State of the Wall: The exterior wall must be in good condition. If it has cracks or the bricks are sagging, then cavity wall insulation would not be a good idea. If your exterior wall is not weatherproof, adding cavity wall insulation may lead to damp problems inside your home.

It is important to note that not all homes are suitable for cavity wall insulation. If you are unsure whether your home is suitable, it is recommended that you consult a professional insulation installer. They will be able to assess your home and advise you on the best course of action.

Does My Home Already Have Cavity Wall Insulation?

To determine if a home already has cavity wall insulation, there are two options available. The first option is to inspect the cavity wall by drilling a hole or removing a brick. The second option is to contact the local council to obtain a record of homes that have cavity wall insulation installed. It is important to note that cavity-filled walls can become damp if not properly installed.

Should I Have Cavity Wall Insulation?

Cavity wall insulation is not suitable for all properties, and it is important to consider certain factors before installing it. While cavity wall insulation can help reduce energy bills and improve the energy efficiency of a home, it can also lead to damp issues if installed in the wrong conditions.

Homes that are exposed to severe wind-driven rain, unsheltered by other houses or trees, or have external walls in poor condition are not suitable for cavity wall insulation. If more than one of these factors are true for a home, it is recommended to seek advice before installing cavity wall insulation.

It is important to speak to an installer if there are any concerns about installing cavity wall insulation, especially if the property is located along the West coast of the UK.

Building Permissions Needed for Cavity Wall Insulation

For cavity wall insulation, planning permission is not required unless the building is listed. However, the installation of cavity wall insulation is subject to building regulations, and therefore a building notice must be submitted. It is the homeowner’s responsibility to ensure that the work is carried out to the expected standard.

Most installers, particularly those registered with the Cavity Insulation Guarantee Agency (CIGA), handle this process. The exterior appearance of the building will not be affected by the work, so planning permission is not required.

Benefits of Cavity Wall Insulation

Cavity wall insulation has several benefits that make it an excellent investment for homeowners.

Reduces Energy Bills

Cavity wall insulation helps to reduce energy bills by preventing heat loss through the walls. According to the Energy Saving Trust website, cavity wall insulation can save homeowners between £70 and £245 per year, depending on the size of their home.

By reducing the amount of heat that is lost through the walls, homeowners can rely less on their central heating system, which means they can save money on their energy bills.

Keeps Property Warmer

Cavity wall insulation can help to keep homes warmer by preventing heat from escaping through the walls. This means that homeowners can enjoy a more comfortable living environment, even when the heating is on. By reducing the amount of heat that is lost through the walls, homeowners can also reduce their reliance on their central heating system, which can help to prolong the lifespan of the system.

Reduces Carbon Footprint

Cavity wall insulation can help to reduce the carbon footprint of a home by reducing the amount of energy that is needed to heat the property. By using less energy to heat the home, homeowners can reduce their impact on the environment. This is a great way to make a positive impact on the planet while also saving money on energy bills.

Increases Property Value

Cavity wall insulation can increase the value of a property by making it more attractive to potential buyers. Most homebuyers expect properties to be well insulated, and by having cavity wall insulation installed, homeowners can demonstrate that their property is well insulated and energy-efficient. This can make the property more appealing to buyers and can help to increase its value.

Overall, cavity wall insulation is an excellent investment for homeowners who want to reduce their energy bills, keep their homes warmer, reduce their carbon footprint, and increase the value of their property.

How to Choose an Insulation Installer

When it comes to choosing an insulation installer, there are several factors to consider to ensure that you get the best possible service. Here are some things to keep in mind:

Accreditations

It is important to choose an installer who is accredited by the Cavity Insulation Guarantee Agency (CIGA) or the British Board of Agreement (BBA). This accreditation shows that the installer is trained and qualified to install insulation, giving you peace of mind that the job will be done properly.

Warranties

Look for an installer who offers a warranty for their work. This will ensure that you are covered if any problems arise after the installation.

Cost

While cost is an important factor, it is not the only one. The cheapest option may not always be the best, as you want to ensure that the job is done properly. Get quotes from several installers before making your decision to ensure that you get the best possible price. You can also save on cost with a cavity wall insulation grant.

Type of Insulation

Not all installers are able to install all types of insulation. Make sure you choose a company that can install the type of insulation you have chosen.

Company Reputation

Ask family and friends for recommendations and read online reviews to get an idea of what other people think of the company. This will give you an idea of the company’s reputation and help you make an informed decision.

Once you have chosen an installer, they will visit your property to assess it and give you a quote. After accepting the quote, they will arrange a date to carry out the work. The installation process is usually quick and shouldn’t take more than a few hours. By keeping these factors in mind, you can choose an insulation installer with confidence and ensure that your home is properly insulated.

Type of Cavity Wall Insulation

Mineral Fibre Costs

Mineral fibres are made from molten rock that is bound together and then either made into sheets or loose fibres. Mineral fibre insulation can be blown into the cavity for easy installation. It is an excellent insulating material that is resistant to rot. However, it is not the most environmentally friendly option. The average cost of mineral fibre insulation is between £13 – £18 per m2.

Wool Fibre Costs

Wool fibre insulation is made from sheep’s wool that can come as loose fibre or as rolls of wool, a little like a blanket. Wool fibre insulation is a good insulating material that can be blown into the cavity for easy installation. It is also a very eco-friendly option. However, it is more expensive than mineral fibre insulation. The average cost of wool fibre insulation is between £25 – £30 per m2.

EPS – Expanding Polystyrene Beads or Granules Costs

EPS, or expanding polystyrene beads or granules, are small beads or granules of polystyrene that are easy to insert into the cavity. They provide excellent heat insulation and are environmentally friendly. However, they offer poor sound insulation. The average cost of EPS insulation is between £18 – £22 per m2.

PUR – Polyurethane Foam Costs

Polyurethane foam is a type of spray foam that is excellent for filling every crack and space in the cavity as it expands as it sets. It is the most efficient insulator and can be easily installed. However, it is an expensive option, and it is not environmentally sound as it cannot be recycled. The average cost of polyurethane foam insulation is between £22-£26 per m2.

Cavity Wall Board Costs

Cavity wall board insulation is designed to fit in the cavity wall space. They come in a range of sizes and materials to suit your needs. However, they are mostly designed to be fitted when the house is built, so they can be hard to retrofit. The average cost of cavity wall board insulation is between £15-£17 per m2.

Urea-Formaldehyde Foam

Urea-formaldehyde foam used to be the standard when it came to cavity wall insulation. However, it is no longer used due to problems with this material. It fails over time, as the foam shrinks significantly, releasing formaldehyde gas, which is a toxic chemical. It should not be used, and if it is injected into the walls, it should be removed and replaced.

Cavity Wall Insulation Grants

Grants are available to cover the cost of cavity wall insulation. However, not everyone is eligible for a full grant. To determine eligibility, individuals must check with their energy supplier. If the energy supplier is part of the Energy Company Obligation (ECO) scheme, the individual can check if they meet the criteria for a grant. Most major energy suppliers, including British Gas, EDF Energy, Eon, Npower, Scottish Power, and SSE, have signed up for the scheme.

The criteria for eligibility vary depending on the energy supplier, but generally depend on how much money the individual would save by getting the insulation. If the savings are not significant, the energy supplier is unlikely to pay for the insulation. The other major consideration is whether the individual receives any benefits.

If an individual is interested in getting a grant, they should contact their energy provider and inquire about an ECO grant or affordable warmth. These are two names for the same scheme. Even if the individual is not eligible for a full grant, they may be able to get some support if their cavity is deemed “hard to treat.” If issues arise during the insulation process, the individual should speak to their energy provider again and see if they can help.

It’s worth noting that free loft insulation may also be available, so individuals should check if they haven’t already got loft insulation. The government insulation grants are available under the Energy Obligation Scheme (ECO).

How Does Cavity Wall Insulation Work?

Cavity wall insulation works by preventing heat loss through convection. In a cavity wall, air can move freely, and when it gets heated up, it rises and escapes through the top of the wall. This creates a convection current that takes heat away from your home.

Cavity wall insulation stops this process by filling the cavity with a material that traps the air and prevents it from moving freely. This added material creates a barrier that stops heat from escaping through the walls.

By reducing the amount of heat that escapes through the walls, cavity wall insulation helps to keep your home warmer and more energy-efficient. It can also help to reduce your heating bills, as you won’t need to use as much energy to keep your home at a comfortable temperature.

How Much Can Cavity Wall Insulation Reduce Energy Bills By?

Cavity wall insulation is a cost-efficient way to reduce energy bills. According to the Energy Saving Trust, up to 1/3 of heat from a home is lost through the walls. Installing cavity wall insulation can reduce bills considerably.

For a terraced home, cavity wall insulation can reduce bills by between £70 and £85 per year. In a detached home, heating bills can drop by as much as £200-£245 per year. These figures are dependent on the type of home and other factors.

How Long Does Cavity Wall Insulation Last?

Properly installed cavity wall insulation should last for the lifetime of a home. The Cavity Wall Insulation Guarantee Agency (CIGA) provides a 25-year guarantee for properly certified installers. Choosing a certified installer ensures proper installation and peace of mind.

Improper installation or allowing damp into the home are the only reasons that would require cavity wall insulation to be removed. A survey should be carried out before the insulation is installed to identify any potential damp issues.

Overall, cavity wall insulation is a long-lasting and effective solution for improving the energy efficiency of a home.

Cost of Removing Cavity Wall Insulation

When it comes to cavity wall insulation, there are certain situations where it may need to be removed. The most common reasons for removal are when the insulation has failed or is allowing damp into the home. Additionally, if urea-formaldehyde foam was used as insulation, it should be removed for health reasons, as it releases a dangerous chemical over time.

Removing Urea Formaldehyde Foam

Removing urea-formaldehyde foam is a difficult and time-consuming process. It involves breaking down the insulation into dust, which is then vacuumed out of the cavity. To ensure that none of the dust gets into the home, the whole house must be secured, and all ventilation routes must be sealed. This means that the job must be carried out with care, and it may be necessary to vacate the home for the duration of the job. Prices for removing urea-formaldehyde foam vary and can be expensive.

Removing Other Types of Insulation

Removing other types of insulation is much easier than removing urea-formaldehyde foam. The bricks at the bottom of the wall are removed, and the insulation is either sucked or pulled out. While it is not difficult, the process is time-consuming. On average, the cost of removing cavity wall insulation is around £21 per m2.

In summary, removing cavity wall insulation can be a difficult and time-consuming process, depending on the type of insulation that was used. While removing other types of insulation is relatively easy, removing urea-formaldehyde foam is a more complicated process that requires careful planning and execution. The cost of removing cavity wall insulation varies depending on the type of insulation and the extent of the job.

Hiring a Cavity Wall Insulation Installer Checklist

When hiring a cavity wall insulation installer, there are a few things to keep in mind to ensure that you get a qualified professional. Here are some tips to follow:

  • Look for installers who are members of the National Insulation Association (NIA), the Cavity Wall Insulation Guarantee Agency (CIGA), or the British Board of Agrément (BBA).
  • Check that the installer has agreed to a professional code of practice.
  • Find out if their work is eligible for the 25-year guarantee offered by CIGA.

Following these guidelines will help ensure that you get a qualified and trustworthy professional to install your cavity wall insulation.

Contact Us For A Free Cavity Wall Insulation Quote

Looking to install cavity wall insulation? Give us a call on 0333 006 8573 or fill out the form on our contact page.

External Rendering & Insulation Specialists

ProGuard Exteriors Ltd is a highly rated external rendering and insulation company providing bespoke packages for homeowners, developers and businesses across South East England.