Fibreglass Roof Cost

Fibreglass roofing, also known as Glass Reinforced Plastic (GRP), has emerged as a durable and cost-effective solution for residential and commercial properties. Made from layers of polyester resin interwoven with glass fibres, it creates a weather-resistant finish with benefits such as longevity and low maintenance that make it a popular choice.

In the UK, GRP roofs are most commonly found on:

• House extensions
• Garage roofs
• Dormer loft conversions
• Porch roofs and balconies

Before opting for a fibreglass roof, it's crucial to understand the various factors that influence its cost. In this guide, we will delve into the key considerations that affect the price of fibreglass roofing, helping homeowners and property owners make informed decisions about this essential construction investment.

Fibreglass Roof Cost Calculator

How Much Does Fibreglass Roofing Cost?

The average cost of a fibreglass roof is around £240 per m² fully installed. What you pay depends mainly on whether you choose a fully insulated fibreglass roof, at £210 to £270 per m², or just a fibreglass roof covering, at £35 to £45 per m².

For the most popular jobs, a small porch or garage roof covering typically costs under £700, while a fully insulated dormer or single-storey extension roof starts from around £2,000 and can rise to over £5,000.

Fibreglass roof installation carries risks, both to the installer and the roof. It's important to have your roof installed by a fibreglass roofing specialist to ensure the best results and safety.

Fibreglass Roofing Prices

To give you an idea of fibreglass roofing costs in context, here are some typical projects to consider:

Is fibreglass cheaper than standard re-roofing?

Depending on your situation, fibreglass roofs can be cheaper to install than a felt roof and EPDM rubber roofs. Here's how:

If you have a small area you need to re-roof (and you know the roof boards are in good condition), a GRP covering will be far cheaper than a standard flat roof installation. This is because a felt flat roof will need re-decking, costing more in both labour and materials, whereas a fibreglass roof covering makes use of your existing roof boards.

For garage roof replacements in particular, GRP is a cost-effective option. Garages typically won't need full insulation, so you only need a GRP layer. A garage re-roof using felt can be almost double the cost of simply using GRP.

Fibreglass Roof Cost per m²

There are two main types of fibreglass roofs commonly used in domestic settings:

• Insulated fibreglass roofs — This is a complete re-roof (new insulation boards, roof decking, completed with a GRP finish), known as a warm roof system. This is suitable for damaged roofs, new builds, or homeowners looking to improve energy efficiency.
• Fibreglass roof coverings — This is a GRP layer applied directly onto your roof's existing decking once the old surface has been stripped away. It's only suitable if the roof decking is in good condition, and it is far cheaper than a full fibreglass roof installation.

Below is a table highlighting the average fibreglass roofing prices in the UK per m²:

What is your main reason for installing fibreglass roofing?

Upgrading an existing roof

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Replacing a leaking or damaged roof

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How Much Does a Fibreglass Roof Cost? (Supply Only)

If you were wondering about the cost of materials for a fibreglass roof, you can expect to pay around £100 to £150 per m².

GRP materials include:

• OSB boards — Wooden boards that make up the flat roof's decking.
• PIR insulation boards — Foam insulation used in warm roof systems.
• Fibreglass matting, resin, and topcoat — The three key layers of GRP.
• Trims and flashing — Finishings that create a watertight seal.

To calculate fibreglass roof costs, you'll need to know your roof's dimensions to determine the overall cost of the materials.

The quality of the materials may affect the overall cost. Higher-quality materials typically cost more.

How Much Does Fibreglass Roof Labour Cost?

A roofer will usually charge an hourly rate or a daily rate:

• The average hourly cost for a roofer is around £25 to £35.
• The average daily rate for a roofer is usually around £200 to £275.

Different roofing companies charge different labour fees. If you are working with a local independent roofing company, you can expect to pay less than if you were to go for a big brand company.

The size of your roof will affect the labour costs. The larger your roof, the more you can expect to pay in labour costs as the job will take longer.

Your location will also play a part. Those based in and around London can expect to pay more for labour costs than those based in other areas of the UK.

What Impacts the Cost of Fibreglass Roof Installation?

There are several things that can affect the overall cost of a fibreglass roof installation. Below, we will go over everything that can affect the overall cost of your fibreglass roof installation.

Size

The size of your roof can affect the overall cost of the job.

Fibreglass roof installations are calculated by square metres. This means that a larger roof will cost more to install than a smaller roof.

A larger roof will take longer to install and will also require more materials, which is why the cost will add up for larger roofs.

Complexity

The complexity of the job can affect the overall cost.

Some roofs may be in an awkward shape or difficult to access. Things like that can make the job take longer to complete, which can result in higher costs.

Labour

Labour costs can vary depending on the type of contractor that you choose and your location in the UK.

Different roofing companies charge different amounts. If you are working with a local independent roofing company, you can expect to pay less than if you were to go for a big brand company.

Location

Those based in and around London and the South East can expect to pay more due to the higher overheads involved. Roofing companies in these areas are often required to pay higher wages than those based in other areas of the UK and, in some cases, this can also have an impact on the supply cost of materials and transportation fees.

Roof Deck Preparation

The condition of the existing roof deck will affect the overall cost of the job.

Your roof deck needs to be in good working order to hold the new roof. If any repairs are needed on the roof deck, this can affect the overall cost of the job. A proper substrate is essential for a fibreglass roof installation.

Fibreglass Roofing Layers

Fibreglass roofs consist of several layers of materials. The number of layers can affect the overall cost of the job.

Also, the quality of the materials can affect the overall cost of the job. You can expect to pay more for materials that are of a higher quality.

Roof Insulation

The average cost for roof insulation in the UK is between £400 and £600. However, this can vary depending on the size and style of roof, as well as the type of insulation you choose. For example, fibreglass insulation is generally less expensive than laying warm deck insulation boards, although it's worth considering which option is most cost-effective for your property.

Additional Features

If you want to get any additional features added to your fibreglass roof, such as skylight installation (around £1,100 on average), this can affect the overall cost.

Additional features will increase the costs, and these increased costs will vary, depending on the job at hand.

Decorating and Finishing

Once the fibreglass roofing has been installed, some finishing work may be required. This can include painting external fascias and soffits for both aesthetic and practical reasons. Applying additional protective coatings can also help improve resistance against adverse weather conditions and general wear and tear.

If you choose to carry out further decorating, such as painting external walls or updating internal areas, this will naturally increase the overall cost of the work.

Scaffolding Costs

When working at height, scaffolding is often required for health and safety, as well as for practical reasons, especially in relation to fitting a new roof.

The extent of the work required and size of the property will affect the cost of hiring scaffolding. It is also important to note that in most instances, scaffolding is hired for a fixed period, often with a minimum of 6 to 8 weeks.

Removing an Existing Roof

If you are replacing or upgrading an existing roof, this also needs to be taken into consideration for the overall cost.

While the removal process is often included as part of your initial quote, the project may run into unexpected complications. The condition of the roof to be replaced is an important factor, especially if any structural damage is uncovered along the way.

If the new fibreglass roof involves a different design, additional building work may be required to ensure it is fitted correctly, which will then increase the cost accordingly.

DIY Fibreglass Roof Installation

DIY fibreglass roofs aren't recommended as there are many challenges and potential hazards involved with this type of work.

GRP roofing requires very careful planning and preparation. It also requires proper installation techniques and certain safety precautions to ensure a successful and durable installation.

Fibreglass rolls are very heavy and will require proper lifting and handling techniques to prevent any injuries. They also need to be accurately cut and measured to fit in with your roof dimensions and ensure proper seams and overlaps.

Fibreglass fibres can be very sharp and irritating, so it's important to wear protective gear such as gloves and overalls to protect your skin. Exposure to resin fumes can cause some respiratory problems, so proper ventilation is needed throughout the entire installation.

Working at height can also be very dangerous and requires certain safety precautions to prevent accidents.

Freshly applied resin can be very hot, and this increases the risk of burns, so protective gear and proper handling are essential.

If you are considering installing a fibreglass roof yourself, it is important that you:

• Have previous experience in roofing.
• Follow all safety guidance and use the correct materials and tools for the job to ensure a safe and successful installation.
• Speak to experienced fibreglass roof installers for advice and insights that may help you with the installation.

In the majority of cases, it's best to leave this type of work to the professionals.

Hiring professionals for the work will ensure that the job is done correctly and safely, giving you peace of mind and also saving you a lot of time.

Fibreglass Roof Maintenance Cost

Fibreglass roofing does require an element of roof maintenance to help avoid any long-term damage and further expense at a later date.

In the below table we summarise some of the additional costs involved in maintaining your roof, before looking at each of these in more detail.

Repair Any Damage

If you see any damage during the inspection, you must address this immediately.

Minor damage can be repaired with a simple fibreglass repair kit. However, larger damage will require professional assistance with the cost of fibreglass repairs largely depending on the extent of the work required.

Trim Nearby Trees and Vegetation

Any overhanging trees or vegetation near the roof may cause scratches or damage to the roof's surface. Although this could be considered garden maintenance, leaving it untouched can also cause further issues such as blocked gutters and drainage.

Be sure to trim back any vegetation or branches that come into contact with the roof.

Inspect Your Roof Regularly

Regular roof inspections are important so that you can detect any signs of damage or wear and tear. Look out for things like holes, cracks, and any other visible signs of damage. Check the gutters, flashing, and drainage systems for any clogs or signs of damage. If in any doubt, hire a roofer to carry out any further reviews.

Clean Your Roof

Fibreglass roofs require regular cleaning to remove any debris, dirt, and algae.

To clean the roof, use a mild detergent and soft-bristled brush to gently clean the surface. Avoid using any abrasive cleaners or high-pressure water, as these could damage the surface of the roof. Alternatively, you can hire a cleaner who specialises in roof cleaning (and in particular, with experience and knowledge of how to treat fibreglass).

Building Regulations and Planning Permission for a Fibreglass Roof

There are certain building regulations that apply to a fibreglass roof. Take a look at the list of building regulations that need to be adhered to below:

• Water needs to drain to one or two edges.
• The roof slope needs to have a minimum fall of 1:80.
• Cold roofs need to be adequately ventilated.
• Waterproofing needs to extend up the adjacent walls at least 150mm from the surface of the roof.
• The roof must be constructed to be resistant to winds and strong enough to step on.
• Warm roofs must have an adequate vapour control layer.

It is important to ensure that the fibreglass roof installation adheres to all building regulations.

A professional fibreglass roof installer should be aware of all building regulations and build the roof to code with these regulations.

Cost of Removing a Fibreglass Roof

On average, you can expect to pay around £60 to £90 per m². This averages to between:

• Small (15m²) — £900 to £1,350 to remove.
• Medium (30m²) — £1,800 to £2,700 to remove.
• Large (50m²+) — £3,000+ to remove.

Those based in and around the London area can expect to pay more for the labour costs of the job than those based in other areas of the UK.

Checklist: Hiring Contractors for Fibreglass Roof Installation in the UK

Ready to get started on your fibreglass roofing project? Here are some points to consider when hiring a local roofer:

• Have you received more than one quote? With the help of MyJobQuote you can gather at least 3 quotes from different local companies so you can compare your costs and find the best deal.
• Do they have positive feedback? Read past reviews on sites such as MyJobQuote, paying close attention to any comments about timekeeping, quality of work, and whether they come recommended by former customers.
• Do they have examples of previous work? Check their company website, MyJobQuote profile, or ask to see a portfolio of work so you can feel confident in their credentials and ability to deliver.
• Does your tradesman have suitable experience? As well as being a fully qualified and experienced roofer, ask about specific jobs regarding fibreglass roofing to ensure they've worked on similar projects.
• Do they have suitable insurance for the job? While it's not a legal requirement, any reputable builder or roofer will at least have public liability insurance in the event of property damage or personal injury.
• Have you received an itemised breakdown? Aside from receiving your quotes, ensure you have everything that's been agreed in writing and individual costs are listed accordingly to avoid unexpected extras.
• Will they provide a guarantee? While it is often expected to have a warranty or guarantee should there be any immediate issues following completion, always request any agreement in writing.

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