Roof Insulation Cost

Last updated 17th November 2023 - Reading time: 13 mins
At a glance
  • The average cost to install roof insulation is around £450
  • The job will take approximately 1 - 2 days to complete
In this article, you'll discover the following:
  • A complete pricing breakdown which includes roof insulation options to consider, along with what such a task usually involves
  • How long the job should approximately take and a general overview of what kind of jobs can be performed
  • How to find and hire a roof insulation installer

Want to know how much it costs to insulate your roof?

In this guide we look at all different types of roof insulation, such as spray foam insulation, warm roof insulation, fibreglass roof insulation, pitched roof insulation and how much you can expect to pay to hire a roof insulation specialist.

Roofing insulation will cost you anywhere between £400 and £600 on average.

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If so, we have a wide range of local roof insulation installers ready to offer you a free quote!

For all roof insulation cost details, check out the article below!

Insulation Top Image

The average cost of Roof Insulation in the UK is:

Depending on the scale and complexity of the job, this usually takes approximately 1-2 days.

£450

How Much Does Roof Insulation Cost?

Installing roof insulation in the UK is estimated to cost between £400-£600, depending on the extent and area of the project. There are many cost-affecting factors to consider when calculating the cost of installing roof insulation to your property.

The cost of installing roof insulation usually depends on the type of roof you have and the materials used. There are a few different methods and materials that can be used to insulate the roof of your property.

In the UK, the majority of homes have what's known as a pitched roof. A pitched roof consists of two sloped sides that run downwards, away from the central ridge of the roof. In order to class a roof as a pitched roof, some regulations state that the angle of the slope needs to exceed 10 degrees or consist of more than two sides over the central ridge.

When insulating a property with a pitched roof, two conventional methods can be used. The insulation material can either be positioned above the roof joists or directly under the slope of the pitch. The cost of your roof insulation project will waver depending on the method of insulating you choose.

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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 Fibre Glass 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, 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 20 Square Metres 1 Day or Less £380-£420
Mineral Wool Rolls Pitched Room 20 Square Metres 1-2 Days £400-£480
Spray Insulation Pitched Roof 20 Square Metres 1 Day or Less £700-£900
Warm Deck Insulation Boards Flat Roof 20 Square Meters 1-2 Days £600-£700
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Supply Only Costs

If you wish to know what the supply only costs 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 Insulation £20-£30
Warm Deck Insulation Boards £15-£20
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Labour Costs and Time Scales

Labour will usually cost £150 to £200 per day, per tradesperson. So, labour costs depend heavily on how long the job will take. Duration of a job will be between 1-2 days; this can change if your loft is larger.

Type of Insulation Type of Roof Area Covered Installation Time
Fibreglass Insulation Pitched Roof 20 Square Metres 1 Day or Less
Mineral Wool Rolls Pitched Room 20 Square Metres 1-2 Days
Spray Insulation Pitched Roof 20 Square Metres 1 Day or Less
Warm Deck Insulation Boards Flat Roof 20 Square Meters 1-2 Days
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What's Involved with Installing Roof Insulation?

Installing roof insulation is a straightforward process, that effectively stops heat from escaping out of your home. While the installation process itself can be relatively easy, we always recommend that for best results, you hire a professional, experienced tradesperson to carry out the job for you.

When hiring a qualified contractor to install insulation to the roof of your property, you should first understand what is involved in the process itself. When hiring a tradesperson to carry out the installation for your home, a roof installation expert will determine the type and size of the roof that needs to be insulated.

They will discuss with you the various options that you can choose from when deciding on the quality and materials you would like to use.

Feel free to ask your tradesperson how each material will benefit your home and always be sure to discuss how each method varies in price. An experienced contractor will easily be able to advise you on what methods and materials they recommend for your specific circumstances.

They will check the ease of access to your roof, assessing for any previously failed insulation that may need removing before carrying out the installation.

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Your insulation specialist will also ensure that the attic space is free of any damp and condensation that could affect the performance of your new insulation. In some cases, it may be necessary for a removals team to visit your property a few days before the installation of your new roof insulation.

Once the space is clean and free of any obstructions, a professional roof insulation crew can begin installing your new insulation. Usually, the process only takes a few hours and is complete within one day or less. However, depending on the complexity of your roof and the scale of the project, this can sometimes take longer.

The most common method of roof insulation is called Warm Roof Insulation, which means that the insulation materials are installed between the weatherproof layer of the roof and its structure or rafters, therefore retaining the heat of the property within.

The opposite method, a Cold Roof Insulation, is not cold as the name depicts. However, this method consists of the insulation being installed above the roof joists, retaining the heat only within the rooms below. This means that any ceiling, attic or room space above the insulation will not maintain as much heat.

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DIY Installing Roof Insulation

Providing that your access to your attic space is clear and free of any obstructions, it is possible to install roof insulation yourself. However, as with any home improvement project, to achieve the best possible performance and finish, we always advise you to hire a professional.

Depending on your access and spacing between the joists and roof, the job will be much easier to carry out yourself.

While the process itself may be straightforward, many steps must be taken before carrying out the installation that you should not overlook.

Preparing the space for your new insulation is extremely important, and if ignored, could result in costly damage to your property.

If you find that your loft space is suffering from damp and condensation, consider properly treating the issue before installing any new insulation.

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Some types of roof insulation will soak up moisture, holding the water in your attic space. This can lead to structural damage and additional problems that will affect your property massively over time. Existing pipework must be appropriately insulated before installing your new roof insulation materials.

If you do not cover the pipes when using a Cold Roof Insulation method, you risk the pipes bursting over time, particularly in freezing conditions, due to the insulation retaining heat in the floors below.

Electrical cables are another hazard that must be attended to properly before installing roof insulation materials. Be sure to leave any wires or cables exposed, so that they do not overheat.

Many roof insulation materials can likely cause health problems if mishandled. Fibreglass insulation is commonly known to cause skin irritation and other wellness problems.

If fibreglass insulation is not sealed correctly, the microscopic glass particles may end up circulating in your property's ventilation system, leading to respiratory problems.

For effective results and the best quality finishes when installing your new roof insulation, it is best to leave the job to an experienced professional.

Roof Insulation Options

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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.

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.

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.

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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, Rock or Mineral wool insulation can be purchased in large mats or rolls and is another budget-friendly option, costing around £20-£25 per square metre.

If you are looking to source an eco-friendlier option, you may like to consider using Sheep wool insulation. Similar to Rock and Fibreglass Wool, the Sheep wool is available in large rolls.

However, this natural alternative is much more expensive to buy and may set you back around £50-£60 per square metre. Sheep wool is much more pleasing to work with and is less of an irritant when compared to other types of insulation.

Plastic or Polyester fibre rolls are similar to Sheep wool insulation, being less of a health hazard to work with. They are also an eco-friendly alternative as they are usually made with recycled materials.

Plastic and polyester insulation is generally cheaper than Sheep wool insulation, but not as affordable as fibreglass. On average, Polyester insulation will cost around £35 per square metre.

Expanding foam insulation is a common choice amongst many homeowners for roof insulation. Thanks to the materials 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.

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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-£40 per square metre.

Hiring a Roof Insulation Installer Checklist

  • Research various professional tradespeople in your area.
  • Be sure to check that your tradesperson is qualified and experienced to carry out the job.
  • Obtain multiple quotes from at least three contractors to ensure that you get the best possible price.
  • Discuss with your tradesperson the various methods of insulation and materials they recommend for your project.
  • Never pay the full amount upfront and always ask for a written cost breakdown
  • If a deposit is required, make sure that you receive proof in writing of any transactions, including the final price.

FAQs

What is the best insulation for a roof?

Fibreglass Wool or Mineral Wool rolls are the most cost-effective solution for insulating a roof. They can be easily installed and offer excellent thermal insulation and soundproofing qualities.

Can you get free loft insulation?

Most homeowners in the UK are eligible to apply for free loft insulation. However, this will depend on your local authorities qualifying criteria. Be sure to check before submitting your application.

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.

What does roof insulation do?

Roof or loft 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.

Can you use spray foam insulation for a roof?

Absolutely. Spray insulation is one of the best choices for insulating a roof. Many professional roof insulation installers will recommend using spray foam insulation as the results out-perform alternative methods.

Sources

https://www.roofingsuperstore.co.uk/
https://www.diy.com/departments/building-supplies/insulation-damp-proofing/DIY763132.cat#Icamp=SRD_insulation
https://www.insulationsuperstore.co.uk/browse/ceiling-roofing.html

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