Potential Cavity Wall Insulation Costs in London

A half built house with cavity wall insulation exposed

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May 14, 2024

There’s a lot that goes into installing cavity wall insulation, regardless of whether you are looking for loft insulation or it’s due to an energy company obligation.

You’ll need to hire an insulation installer, consider building regulations and potentially organise removing the old cavity wall insulation if you already have some in place. Before getting started you need to consider the type of insulation and costs involved.

Average Costs for Cavity Wall Insulation in London

Total Costs

The average cost of cavity wall insulation in London ranges from £500 to £1,500.

It’s hard to give an exact price for the cost of cavity wall insulation in London, as there are a variety of things that impact the cost. For example, it’s cheaper to install cavity wall insulation in a small home than it is in a much larger property. The cost also varies depending on the type of home, the type of material used and the tradesman that you choose. This is why it’s important to look at the average costs.

Costs Per Metre Squared

One of the simplest ways to determine the cost of cavity wall insulation is to determine the cost per metre squared, and then work out how large the space is that you need to insulate.

  • For a detached house, you should budget an average cost of £20 – £35 per square metre. For a semi-detached house, the cost is closer to £15 to £30.
  • For a mid-terrace house, you will be looking at anywhere between £10 and £25 per square metre for cavity wall insulation, and between £15 to £30 for an end of terrace house.
  • Adding cavity wall insulation to a bungalow is slightly higher, at between £20 and £30 per square metre.

Costs for Insulation

The cost of cavity wall insulation varies hugely, depending on the type of insulation that you choose and the size of the property. Unsurprisingly, it’s cheaper to add cavity wall insulation to a smaller space, and larger homes tend to cost considerably more.

For example, the average cost of adding cavity wall insulation in a mid-terrace home tends to be between £300 and £600. This cost rises to between £600 and £800 for a semi-detached home, and between £800 and £1,200 for a large detached home.

Installation Costs

When you hire a professional tradesmen to install cavity wall insulation in your home, you need to factor in the cost of installation. This refers to the cost of labour required to complete the project.

The total installation cost for cavity wall insulation is based on the type and size of your house, as well as how long the project will take. On average, the cost of labour for a mid floor flat is between £100 and £200.

This increases for larger properties, with terraced houses requiring between £200 and £350 of labour, and semi-detached homes requiring between £300 and £450 of labour.

If you have a detached bungalow, the cost is likely to be closer to between £400 and £550.

For a detached house, this increases again, rising to between £500 and £650.

Factors Affecting Costs

When you are considering cavity wall insulation, it’s important to understand the various factors that can influence the overall cost of the project. This will help you to budget correctly, and determine how much you are roughly going to have to spend on insulating your home.

Labour Costs

Labour costs play a big part in determining the overall expense of cavity wall insulation. The complexity of the installation process, as well as the expertise and experience of the installation team, can impact labour costs. Additionally, factors such as location and accessibility of the property may also affect labour charges.

Size of the Home

The size of your home directly impacts the amount of insulation material required for the project. Larger properties will naturally incur higher insulation costs compared to smaller ones, as more materials and labour are needed to complete the installation process.

Complexity of the Installation

The complexity of the installation can vary depending on factors such as the layout of the property, the presence of obstacles like pipework or electrical wiring, and the condition of the existing walls. More complex installations may require additional time and expertise, leading to higher overall costs.

Type and Quality of Insulation Material Used

The type and the quality of insulation material chosen for your project will also impact the overall cost. While there are various types of insulation materials available, such as blown mineral, foam board, or polyurethane foam insulation, each comes with its own price point. Higher quality materials may have a higher upfront cost but can provide better insulation and energy efficiency in the long run.

Any Pre Installation Work Required

Before installing cavity wall insulation, certain pre-installation work may be necessary, such as cleaning or repairing the existing walls. These additional tasks can add to the overall cost of the project, as more time and labour is required, so it’s essential to factor them into your budget from the outset.

Different Types of Cavity Wall Insulation – Costs

A man fitting insulation

Blown Mineral Insulation

Blown mineral insulation is made from liquefied rock that is formed into either sheets or loose fibres. This versatile insulation material can be effortlessly blown into the cavity, making for a convenient installation process.

Known for its superb insulating properties and resistance to decay, blown mineral fibre insulation stands out as a durable and popular choice. However, it’s worth noting that it may not be the most environmentally conscious option available, which is something to remember if you are eco-conscious.

On average, the cost of blown mineral insulation ranges between £13 to £18 per square metre, making it a competitive choice if you are looking for effective insulation solutions.

Polystyrene Bead Insulation

Polystyrene beads insulation – which is also known as EPS, standing for expanding polystyrene beads or granules – comprises small particles of polystyrene that can be effortlessly inserted into the cavity.

It’s known for its exceptional thermal insulation properties, which makes it a good insulation option, and EPS is also chosen for its eco-friendliness.

You can expect to invest an average of £18 to £22 per square metre for polystyrene bead insulation, making it a competitive option for those prioritising both insulation effectiveness and environmental considerations.

Foam Board Insulation

Cavity wall board insulation is specifically crafted to snugly fit within the cavity wall space, offering versatility in sizes and materials to cater to various requirements. However, these insulation boards are primarily intended for installation during the construction phase, which can be challenging if you want to add insulation at a later date.

If you are exploring this option, you can expect an average cost ranging between £15 to £17 per square metre. Using foam board insulation requires careful planning and consideration, especially if you’re looking to add cavity wall insulation into existing structures.

Polyurethane Foam Insulation

On average, the cost of polyurethane foam insulation ranges from £22 to £26 per square metre.

Polyurethane foam stands out as a versatile spray foam that fills gaps and crevices within the cavity, expanding as it cures, and providing a high quality insulation. Known for its exceptional insulation properties, it’s easy to install, making it a popular choice.

However, it’s important to remember that polyurethane foam is one of the most expensive insulation options and it does have an environmental impact, as polyurethane foam cannot be recycled.

Urea Formaldehyde Foam Insulation

Though it was once a commonplace choice for cavity wall insulation, urea-formaldehyde foam has fallen out of favour. Over time, urea-formaldehyde foam exhibits significant shrinkage, leading to the release of formaldehyde gas, which is a toxic substance.

This means that its usage has been discontinued, and it’s no longer a cavity wall insulation option for homeowners. In fact, if you do have urea-formaldehyde foam in your home, removal and replacement are strongly advised.

Do You Have Cavity or Solid Walls?

Determining whether your walls are cavity or solid is key, especially if you are considering your various insulation options. Homes built before the 1920s tend to have solid walls, and those built after this time period are more likely to have cavity walls. However, this is not always the case, as construction methods varied over time. But, it’s a good place to start when deciding which type of walls you have.

You can often tell by examining the external walls of your property. If the brickwork appears uniform and even, with no visible horizontal lines, it is likely that you have solid walls. But, if you notice regular rows of small holes or bricks set slightly back from the face of the wall, it is a sign of a cavity wall.

Wall thickness can also be a determining factor, so consider measuring the thickness of your walls. Solid walls tend to be thicker than cavity walls, often exceeding 9 inches in width. Cavity walls, on the other hand, tend to be thinner, ranging from 9 to 11 inches.

Your construction plans or documents about the property could tell you if you have cavity or solid walls. If available, refer to the original construction plans or documents for your property.

These records may specify the type of walls used during the building process. You could also conduct a tap test by gently tapping on the wall surface. Solid walls produce a dull, low pitched sound, while cavity walls generate a hollow, higher pitched sound.

Benefits of Cavity Wall Insulation

A front room

There’s a lot that goes into keeping a home warm, comfortable and insulated, and doing so often requires the help of cavity wall insulation. Though there are a range of insulation options for homes in London, there’s no denying the benefits of cavity wall insulation. It’s an effective way of keeping rooms warm and energy costs low.

Warmer Rooms

Cavity wall insulation acts as a thermal barrier, effectively trapping heat within the home during colder months.

By filling the empty cavity between the walls with insulating material, such as foam or blown mineral, heat loss through the walls is significantly reduced. This results in a more consistent and comfortable indoor temperature, with fewer cold spots and drafts. As a result, you can enjoy cosier living spaces and say goodbye to chilly rooms.

Cheaper Energy Costs

One of the most compelling benefits of cavity wall insulation is its potential to reduce your energy bills. By improving the thermal efficiency of the home, less heat is required to maintain a comfortable indoor temperature. This means reduced reliance on heating systems, leading to lower energy consumption and substantial cost savings over time.

You can expect to see a noticeable decrease in your heating bills after you have had insulation installed, making cavity wall insulation a wise investment if you are looking for long term financial benefits.

Reduce Carbon Footprint

In addition to financial savings, cavity wall insulation offers environmental benefits by helping to reduce carbon emissions. By conserving energy and lowering heating requirements, you can lessen your household’s carbon footprint and contribute to global efforts to combat climate change.

With eco-friendly insulation materials readily available, cavity wall insulation presents an opportunity to embrace sustainability while enhancing the comfort of your home.

Increase the Property Value

Investing in cavity wall insulation can increase the value of your property. Energy efficient features, including insulation upgrades, are highly sought after by prospective buyers who are increasingly prioritising sustainability and cost savings.

A well insulated home not only offers improved comfort and lower utility bills to new owners but also boasts a competitive edge in the property market.

Whether you are planning to sell or rent out your property in the future, you can use cavity wall insulation as a valuable selling point and maximise the returns on your investment.

Getting Free Cavity Wall Insulation

There are government schemes and initiatives aimed at providing free cavity wall insulation to eligible homeowners. These schemes are primarily designed to improve energy efficiency, reduce carbon emissions and lower heating bills.

Typically, qualifying criteria involve factors such as property type, age and income level. Many energy companies also offer free cavity wall insulation as part of their energy saving efforts, often targeting households deemed vulnerable or in need of assistance.

You can check your eligibility and apply through government websites, local authorities or energy providers.

DIY Vs Hiring a Professional

A smiling tradesman

When it comes to cavity wall insulation, there are two ways to approach things. You can choose to handle the project yourself, or you can choose to enlist the help of a trained professional. There are pros and cons of both, which we have explained below.

The Pros of a DIY Cavity Wall Insulation

  • Cost Savings – One of the most significant advantages of the DIY approach is that it’s the cheaper way to approach cavity wall insulation. By bypassing labour fees, you can significantly reduce the overall expense of cavity wall insulation.
  • Flexibility and Control – A lot of DIY enthusiasts enjoy having the freedom to plan and execute an insulation project according to their preferences. This includes choosing insulation materials, scheduling installation, and overseeing every aspect of the process.

The Cons of a DIY Cavity Wall Insulation

  • Skill and Knowledge Required – Cavity wall insulation is a complex task that requires a certain level of skill and expertise. Without proper knowledge of insulation techniques and materials, DIY attempts can result in subpar insulation quality or even damage to the property. This can be costly to fix.
  • Time and Effort – DIY cavity wall insulation is a time consuming task, one that demands meticulous attention to detail. From preparing the walls to installing the insulation, and then sealing any gaps, the process can be labour intensive and time consuming.
  • Risk of Errors – Inexperienced homeowners run the risk of making mistakes during the insulation process, such as insufficient insulation coverage or improper installation techniques. These errors can compromise the effectiveness of the insulation, and require costly repairs further down the line.

The Pros of a Professional Cavity Wall Insulation

  • Experience – Professional contractors bring years of experience and knowledge to the table, which you are unlikely to have. They understand the intricacies of cavity wall insulation and can ensure proper installation, maximising its effectiveness.
  • Quality Assurance – Hiring a professional provides peace of mind knowing that the insulation will be installed correctly and up to industry standards. This minimises the risk of issues such as inadequate coverage or insulation settling over time.
  • Time Saving – Professionals work efficiently and have access to advanced equipment, enabling them to complete the insulation project in a timely manner. This frees up your schedule and minimises disruption to your daily routine.

The Cons of a Professional Cavity Wall Insulation

  • Cost – The main downside of hiring a professional is the cost. Professional cavity wall insulation can be expensive, especially when factoring in labour fees and materials.
  • Limited Involvement – Opting for professional installation means relinquishing control over the project to the contractor. While this ensures expertise and efficiency, you might prefer a hands on approach to home improvement.

Finding Someone to Install Cavity Wall Insulation

When it comes to finding a contractor for your cavity wall insulation, there are several avenues you can explore. One approach is seeking recommendations from friends, family, or neighbours, as word-of-mouth referrals tend to lead to trustworthy and reliable professionals.

You can choose a tradesman that someone has recommended, knowing that they’ve had a good experience with them. Another option is to use online directories or platforms like The Page, specialising in home improvement services.

This gives you the chance to peruse reviews and compare ratings from previous clients, and find out more about the quality of services being offered.

The Page

Finding the perfect tradesman for your cavity wall installation project in London is made easy at The Page. Simply submit your enquiry, and our team of experts will match you with a handpicked selection of tradesmen, highlighting those that have been tailored to your specific requirements.

Let The Page send you a free bespoke shortlist of tradespeople suited to you and the job you need doing.

There’s no more sifting through endless listings online, nor is there any wondering if someone will provide a professional service, as all of the tradesmen listed at The Page have been personally vetted and their previous work has been thoroughly assessed. With our stringent selection process, you can trust that you’ll be connected with highly qualified professionals experienced in cavity wall insulation.

Whether you’re seeking skilled craftsmen or expert contractors, we’ll ensure that you find the right fit for your project.

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