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myRoof Insulation Cost
At a Glance
- The average cost of roof insulation is about £450 (supply and labour).
- It typically takes around 1 to 2 days to complete this type of job.
- How much different types of roof insulation cost in 2026, with a breakdown of what you can expect to pay per square metre for different materials.
- How long insulating a roof takes, and an overview of what's involved.
- How to find a local roof insulation installer using MyJobQuote.
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Looking into how much roof insulation costs?
In 2026, the average cost of roof insulation is between £400 and £600.
However, the prices you're quoted by an installer will depend on various factors — including the type of roof you have, the material you want to use, and how much is required.
In this guide, we cover everything you need to know so that you can calculate how much roof insulation costs to get professionally fitted in 2026.
This guide covers roof-level insulation specifically — fitted at the rafters or directly beneath the roof covering. If you're looking to insulate the floor of your loft instead, see our loft insulation cost guide.
This includes costs for all the different types of roof insulation, such as spray foam insulation, warm roof insulation, fibreglass roof insulation, and pitched roof insulation.
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For all roof insulation cost details, check out the article below!
£450
Table of Contents
- How Much Is Roof Insulation?
- Cost of Installing Roof Insulation (Labour Only)
- Warm Roof vs Cold Roof Insulation
- Roof Insulation Options
- Is Replacing Roof Insulation More Expensive Than a New Installation?
- Building Regulations & Planning Permission for Roof Insulation
- What's Involved with Installing Roof Insulation?
- Checklist: Hiring a Roof Insulation Installer
- FAQs
Roof Insulation Cost Calculator
How Much Is Roof Insulation?
In 2026, the average cost of professional roof insulation in the UK is between £400 and £600. However, the exact price you're quoted will depends on several factors:
- Type of Roof — Are you looking to install roof insulation on a pitched or flat roof?
- Material — There are a number of options here, including fibreglass, mineral wool, PIR boards, or spray foam. Material costs and how long the job takes will vary depending on what's the best material option in your circumstances.
- Size and Shape — Larger areas and awkward spaces mean that more materials are required and the job takes longer, which means you'll get charged more for labour.
- Location — Labour costs tend to be lower in North England, Wales, and Scotland.
In the UK, most homes have a pitched roof, which is where two sloped sides meet at a central ridge. A roof is usually classed as pitched if the slope exceeds about 10 degrees or it has more than two sides over the ridge.
For pitched roofs, insulation is fitted at roof level, either between the rafters (warm roof) or above the rafters under the roof covering. This is different to loft floor insulation, which sits between the ceiling joists below.
There are also many kinds of different materials that can be used to insulate the roof of a property sufficiently. Some of the most common types of roof insulation include fibreglass insulation, insulation boards or panels, and expanding insulating foam.
Both the quality and kind of insulation material you use will determine how much the job will cost. When hiring a professional tradesperson to carry out the task of insulating your roof, you will likely need to consider that they will charge either an hourly or daily charge, thus affecting the total cost of your project.
What's the best type of roof insulation boards to use? Is thicker always better?
"The thicker the insulation, the better it works to reduce heat flow from the inside of a home to the outside during winter, and from outside to inside during summer."
Roof Insulation Prices
As we previously mentioned, many cost-affecting factors will determine how much installing roof insulation is going to cost. To make things easier for you, we have included a few examples below to see how the varying factors will alter the charge.
Please note that all of the prices included in the table below are estimates and should be used as a guide for demonstrative purposes only. Gaining a quote from a professional tradesperson will give you the most accurate price for your project.
| Type of Insulation | Type of Roof | Area Covered | Installation Time | Cost |
|---|---|---|---|---|
| Fibreglass Insulation | Pitched Roof | 20m² | 1 Day or Less | £380 – £420 |
| Mineral Wool Rolls | Pitched Roof | 20m² | 1 – 2 Days | £400 – £480 |
| Spray Insulation | Pitched Roof | 20m² | 1 Day or Less | £700 – £900 |
| Warm Deck Insulation Boards | Flat Roof | 20m² | 1 – 2 Days | £600 – £700 |
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Roof Insulation Cost Per m²
If you want to estimate costs based on the size of your roof, here's what to expect per square metre, including both materials and labour:
| Type of Insulation | Materials Cost (per m²) | Labour Cost (per m²) | Total Cost (per m²) |
|---|---|---|---|
| Fibreglass or Mineral Wool | £4–£9 | £10–£15 | £14–£24 |
| PIR Boards (Warm Deck) | £15–£40 | £10–£20 | £25–£60 |
| Spray Foam | £20–£30 | £15–£25 | £35–£55 |
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Labour rates per square metre tend to be higher for smaller jobs, as installers still need to cover setup and access time regardless of roof size. Larger roofs typically see a lower per-m² labour cost.
What is your main reason for installing roof insulation?
Reducing energy bills
17 votes - 59%59% of votes
Improving home comfort
8 votes - 28%28% of votes
Increasing property value
2 votes - 7%7% of votes
Eco-friendliness
2 votes - 7%7% of votes
29 votes
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Cost of Installing Roof Insulation (Labour Only)
Labour will usually cost £150 to £200 per day, per tradesperson, and typically accounts for around 40% to 50% of the total cost of roof insulation.
The installation costs of roof insulation typically cover the labour, setup, and basic waste removal, though it is always worth confirming this when requesting quotes. In most cases, materials are supplied and fitted by the installer as part of the overall cost.
The total labour cost will depend on how long the job takes, based on the type of roof insulation you choose and the size of your roof.
For example:
- Fibreglass or spray foam on a pitched roof can often be completed in a day or less, putting your labour costs at around £150 to £200.
- Mineral wool rolls or warm deck board installation may take up to two days, bringing labour costs to around £300 to £400.
Job duration typically ranges from 1 to 2 days, depending on roof size and the insulation method used. Larger or more complex roofs, such as those with multiple sections or steep pitches, may take longer.
| Type of Insulation | Type of Roof | Area Covered | Installation Time |
|---|---|---|---|
| Fibreglass Insulation | Pitched Roof | 20m² | 1 Day or Less |
| Mineral Wool Rolls | Pitched Room | 20m² | 1 – 2 Days |
| Spray Foam | Pitched Roof | 20m² | 1 Day or Less |
| Warm Deck Insulation Boards (PIR) | Flat Roof | 20m² | 1 – 2 Days |
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Warm Roof vs Cold Roof Insulation
There are two main approaches to insulating a pitched roof, and the right one depends on how you plan to use the space above.
| Method | Where It's Fitted | Best For |
|---|---|---|
| Warm Roof | Between or above the rafters, below the roof covering | Loft conversions, habitable roof spaces, reducing ice damming |
| Cold Roof | Above the ceiling joists, below the roof space | Unused lofts, standard insulation upgrades |
Key points to consider for each method:
- Warm roof — Keeps the entire roof space warm, including any loft area above the insulation. Requires more material and is typically the costlier option, but suits roofs being converted into living space.
- Cold roof — Keeps the roof space itself cold while insulating the rooms below. It's the more affordable and common method for roofs that aren't being used as living space.
If you're planning major structural work at the same time, see our roof installation guide for methods and costs.
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Roof Insulation Options
As we briefly covered earlier, there are many different methods of roof insulation and materials that can be used to achieve effective results. Insulating the roof of your property is proven to be one of the most efficient ways of saving energy and reducing household running costs.
A well-insulated home is estimated to save the homeowner a whopping £250 per year on energy bills alone.
Roughly 25% of heat is emitted through the roofs of un-insulated properties, so choosing the right method of insulation is essential.
Based on these savings, roof insulation typically pays for itself within 2 to 3 years, after which the reduction in energy bills continues for as long as the insulation remains effective, often 25 years or more.
If you wish to know what the supply only costs per square metre are, have a look at the table below for prices of the insulation without the cost of labour:
| Type of Insulation | Cost Per Square Metre |
|---|---|
| Fibreglass Insulation | £4 – £6 |
| Mineral Wool Rolls | £5 – £9 |
| Spray Foam | £20 – £30 |
| Warm Deck Insulation Boards (PIR) | £15 – £40 |
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How much does increasing insulation thickness raise a room’s temperature? Does it work like that, or is it more complex?
"There is a little bit more involved. There are a few different materials on the market, and it also depends on the location of the room and the construction type, as well as the heating/cooling system and windows/doors. As we all know, heat rises and will escape from any place it can."
Fibreglass Wool Insulation Cost
The most popular choice amongst homeowners for roof insulation is Fibreglass Wool. Thin strands of glass are heated and spun to create a thick fibre that, as the name suggests, resembles wool.
For roofs, fibreglass wool is most commonly fitted between rafters on a cold roof, with a vapour barrier added to manage condensation. It's less common on warm roof builds, where rigid boards are typically preferred.
This excellent insulator is a great budget choice and can be purchased in long rolls, making it a cost-effective solution. On average, Fibreglass Wool insulation costs around £25 per square metre.
Here is what you can expect to pay for materials depending on your house size:
| House Type | Area | Materials Cost |
|---|---|---|
| Terraced | 40m² | £160–£240 |
| Semi-Detached | 55m² | £220–£330 |
| Detached | 90m² | £360–£540 |
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Mineral Wool Insulation Cost
Similar to Fibreglass wool is Mineral wool Insulation. In this case, rocks such as dolomite are heated and spun repeatedly to create a dense, wool-like fibre.
Like fibreglass, mineral wool is generally fitted between the rafters on a cold roof rather than above them, and needs a vapour control layer to prevent moisture build-up.
Like Fibreglass, Rock or Mineral wool insulation can be purchased in large mats or rolls and is another budget-friendly option, costing around £20 to £25 per square metre.
Material costs will vary depending on the size of your roof:
| House Type | Area | Materials Cost |
|---|---|---|
| Terraced | 40m² | £200–£360 |
| Semi-Detached | 55m² | £275–£495 |
| Detached | 90m² | £450–£810 |
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PIR Boards (Warm Deck) Cost
PIR insulation boards are widely used in warm deck systems, especially for flat roof replacement projects. They offer strong thermal performance with less thickness compared to rolls, but are generally more expensive. Expect to pay around £15–£40 per m² (supply only), or higher once fitted.
Here is how material costs break down across different house sizes:
| House Type | Area | Materials Cost |
|---|---|---|
| Terraced | 40m² | £600–£1,600 |
| Semi-Detached | 55m² | £825–£2,200 |
| Detached | 90m² | £1,350–£3,600 |
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Flat Roof Insulation Cost
Flat roofs are insulated differently to pitched roofs, using either a warm deck or cold deck method. Warm deck insulation is fitted above the roof deck and below the waterproof membrane, which is the most common and effective approach for UK flat roofs. Cold deck insulation is fitted between the roof joists below the deck, but is less common today due to a higher risk of condensation.
Flat roof insulation typically costs £30 to £35 per square metre installed, using PIR boards in a warm deck system. Where a full flat roof replacement is needed alongside insulation, costs can rise to £50 to £100 per square metre.
| Flat Roof Size | Typical Cost (Warm Deck) |
|---|---|
| 10m² (e.g. small extension or garage) | £300–£350 |
| 20m² (e.g. single-storey extension) | £600–£700 |
| 40m² (e.g. larger flat-roofed extension) | £1,200–£1,400 |
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Sheep Wool and Polyester Insulation Cost
Sheep wool and polyester are eco-friendly alternatives, generally fitted between rafters in the same way as fibreglass or mineral wool. Sheep wool costs around £50 to £60 per square metre, while polyester is more affordable at around £35 per square metre. Both are pleasant to handle and pose less of a skin or respiratory irritation risk than glass-based materials.
Spray Foam Insulation Cost
Expanding foam insulation is a common choice amongst many homeowners for roof insulation. Thanks to the material's fantastic resistance to heat flow, spray expanding foam is a very effective insulator.
Due to the spray application, the expanding foam will achieve a better air-tight seal in smaller cavities, reducing heat loss.
While the initial cost may be higher compared to alternative insulation materials, it is expected that you will save more money in the long run on energy expenses. Spray foam insulation costs, on average, around £35 to £40 per square metre.
Material costs for spray foam will depend on the size of your roof:
| House Type | Area | Materials Cost |
|---|---|---|
| Terraced | 40m² | £800–£1,200 |
| Semi-Detached | 55m² | £1,100–£1,650 |
| Detached | 90m² | £1,800–£2,700 |
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Be aware that some lenders and valuers may be cautious about spray foam on roof structures without a professional assessment of ventilation and timber condition. You should get advice from a qualified installer and check with your lender before proceeding.
Is Replacing Roof Insulation More Expensive Than a New Installation?
Replacing existing roof insulation usually costs more than fitting insulation for the first time. This is mainly because of the added labour and disposal costs involved in removing the old material before new insulation can go in.
As a guide, removing and disposing of old roof insulation typically adds £250 to £400 on top of standard installation costs. If the existing insulation is spray foam, removal is more involved and averages £40 per square metre.
If your existing insulation is dry, undamaged, and simply below the recommended thickness, topping it up may be a cheaper option than full replacement. A qualified installer can assess whether your current insulation is suitable to build on.
Building Regulations & Planning Permission for Roof Insulation
Building Regulations
Roof insulation work must comply with Building Regulations Part L, which covers thermal performance, and Part C, which covers condensation and ventilation.
Your roof insulation installer should ensure that the work meets both, but if you have any concerns, you can ask your local authority building control department for advice.
Planning Permission
In most cases, roof insulation does not require planning permission as it does not alter the appearance or structure of your property. However, if you live in a listed building or a conservation area, it is worth checking with your local authority before work begins.
If you are unsure about either, a qualified installer can advise you based on your specific circumstances.
What's Involved with Installing Roof Insulation?
Installing roof insulation might sound simple, but it’s not usually a DIY-friendly job. Working in confined spaces, handling bulky materials, and ensuring the correct fit all require experience.
For best results, most homeowners hire a qualified insulation installer rather than attempting it themselves.
It’s also recommended to get multiple quotes before going ahead. With MyJobQuote, you can get quotes from roof insulation specialists near you. It's fast, free, and there's no obligation to go ahead.
Here’s what to expect from the process:
Before the Job Starts
- Initial Assessment — The installer will measure your roof and check for any failed insulation. They’ll also look for signs of damp or condensation that need to be resolved before work begins.
- Discussing Options — You’ll go through different materials such as fibreglass rolls, PIR boards, or spray foam. The installer will explain how each affects cost and performance.
- Preparation — The roof space must be clear and accessible. Old insulation may need to be removed, and in some cases a removals team will prepare the space before installation.
During the Job
- Fitting the Insulation — The new insulation is installed according to your chosen method. Smaller jobs can take a few hours, while more complex roofs may take 1–2 days.
- Warm Roof Method — Insulation is fitted between or above the rafters, below the roof covering, keeping the entire roof space warm.
- Cold Roof Method — Insulation is fitted above the ceiling joists, below the roof space, which keeps the rooms below warm while the roof space itself stays cold.
After the Job
- Final Checks — The installer will ensure everything is fitted correctly and that there are no gaps or issues that could reduce performance.
Checklist: Hiring a Roof Insulation Installer
Here are some of the things you should consider when hiring a specialist to install your roof insulation:
- Are they a member of the National Insulation Association? The NIA is the main trade body for insulation installers in the UK. Membership shows they meet industry standards and follow a professional code of conduct.
- Are they TrustMark registered? Roof insulation installers that are registered with this government-endorsed scheme are vetted for quality work, trading practices, and customer service.
- Do they hold PAS 2030 certification? This is required for installers carrying out insulation work under government-funded schemes such as ECO4.
- Do they have insurance? Public liability insurance protects you if something goes wrong during the installation.
- Will they provide an itemised quote? Ask for a full breakdown of costs so you know exactly what's included and whether there are any additional fees.
- Is waste removal included? Confirm that the disposal of any old insulation material or packaging is included in the total cost quoted.
- Are they experienced with your type of roof insulation? There are several methods and materials used for roof insulation. Make sure the installer has specific experience with the type of insulation you're having fitted.
- Do they have examples of similar work? Ask to see photos of previous roof insulation jobs or check their MyJobQuote profile for examples of completed installations.
- Do they have positive reviews? Check their MyJobQuote profile to read feedback from previous customers.
FAQs
What does roof insulation do?
Roof insulation works by limiting and reducing the amount of heat loss through the roof of your property. This will ultimately result in a warmer home and lower energy use.
Does roof insulation affect ventilation?
Yes. Insulation reduces air movement, so correct ventilation and vapour control are essential to prevent condensation and damp. Professional installers ensure ventilation is maintained.
What is the best insulation for a roof?
The best option depends on your roof type and budget. PIR boards offer strong thermal performance in less thickness, making them popular for flat roofs and tight spaces. Mineral wool is a cost-effective choice for pitched roofs with standard rafter depths. Spray foam suits irregular roof shapes but carries mortgage-related risks, covered later in this guide.
Can I get funding for roof insulation?
Government schemes like ECO4 and the Great British Insulation Scheme can help cover the cost of insulation for some homeowners in the UK. These schemes typically fund loft floor insulation rather than roof-level insulation, so check eligibility with your energy supplier and confirm which type of insulation is covered.
How do I know if my roof insulation needs replacing?
Two of the most recognisable signs that your roof insulation may need replacing are high energy bills and irregular property temperatures. If you are concerned that your insulation needs replacing, consider seeking the advice of an experienced roof insulation installer.
How long does roof insulation last?
High-quality roof insulation can last 25–40 years if installed correctly. Performance may decline if the insulation gets damp, compressed, or damaged.
How thick should roof insulation be?
Thickness varies by material and target U-value. PIR boards need less thickness than mineral wool to achieve similar performance. Your installer will specify thickness for your roof type.
Can I install roof insulation myself?
Providing your roof space is clear and accessible, it is possible to install some roof insulation yourself. However, working at roof level often involves confined spaces and awkward angles, and mistakes can lead to costly damage or ventilation problems if ignored. Some insulation materials can also cause skin irritation and respiratory problems if not handled correctly. For the best results, we always advise hiring a professional.
