An independent roofing contractor based in the West Midlands specialising in domestic roof projects throughout the UK
An independent roofing contractor based in the West Midlands specialising in domestic roof projects throughout the UK
To do fibreglass roofing, start by preparing a clean, dry, and smooth roof deck, ensuring all surfaces are free from dust and debris. Apply a roofing resin evenly, then lay the fibreglass mat over the surface and saturate it with more resin using a roller to remove air bubbles. Once the resin has fully cured, apply a protective topcoat to create a durable, waterproof, and UV-resistant finish. Proper installation and curing are essential for achieving a long-lasting fibreglass roof.
Fibreglass roofing has become one of the most trusted flat roofing systems in the UK thanks to its strength, weather resistance, and long lifespan. Whether you’re replacing an ageing felt roof or installing a brand-new flat roof on an extension, garage, or garden room, fibreglass roofing offers a seamless and highly durable solution. At S. Tomic Roofing LTD, we understand the importance of using high-quality materials and proven installation techniques to ensure every fibreglass roof delivers long-lasting performance and reliable protection against the British weather.
Fibreglass roofing, commonly known as GRP (Glass Reinforced Plastic) roofing, is a roofing system made by combining polyester resin with chopped strand fibreglass matting. Once the resin cures, it forms a seamless, waterproof membrane that is incredibly strong and resistant to weather damage.
Unlike traditional roofing felt, fibreglass roofing has no joins or seams where water can penetrate. This makes it one of the most reliable choices for flat roofs throughout the UK.
Before learning how to install it, it’s worth understanding why fibreglass roofing has become so popular.
A professionally installed fibreglass roof can last between 25 and 40 years with very little maintenance.
The seamless finish prevents water ingress, reducing the risk of leaks.
Fibreglass roofs require only occasional cleaning and yearly inspections.
They perform exceptionally well in heavy rain, frost, and strong sunshine.
The smooth finish enhances the appearance of garages, home extensions, balconies, and commercial properties.
Although lightweight, fibreglass provides outstanding structural strength and impact resistance.
To complete a fibreglass roofing installation successfully, you’ll need:
Using quality materials is essential if you want a roof that performs well for many years.
Preparation is the most important stage of the installation process.
The roof deck must be:
Most installers recommend OSB3 boards because they provide the ideal base for fibreglass roofing systems.
Never apply fibreglass over damp timber, as trapped moisture can reduce adhesion and shorten the roof’s lifespan.
Before laying the fibreglass matting, fit all necessary trims.
These include:
The trims help direct rainwater into the gutter while giving the roof a neat professional finish.
Ensure every trim is securely fixed before moving on.
Measure each section of the roof carefully before cutting the chopped strand mat.
Avoid stretching the material.
Each piece should lie flat with minimal overlap.
Proper planning at this stage helps reduce waste and speeds up installation.
The polyester resin must be mixed with the correct quantity of catalyst.
The amount of hardener depends on temperature and the manufacturer’s recommendations.
Only prepare enough resin for immediate use because curing begins quickly.
Incorrect mixing can result in:
Always follow the product instructions carefully.
Using a roller, spread an even layer of resin across the prepared roof deck.
Avoid applying excessive resin.
The aim is to create an even coating ready to receive the fibreglass mat.
Work methodically to prevent the resin curing before the mat is applied.
Position the chopped strand mat onto the wet resin.
Smooth it gently into place without creating wrinkles.
Ensure every area is fully covered.
This layer provides the roof’s strength and reinforcement.
Roll additional resin over the fibreglass until it becomes fully saturated.
Use a laminating roller to remove trapped air bubbles.
Air pockets weaken the roof and can eventually cause failure.
Continue this process until every section is complete.
The resin needs sufficient time to harden completely.
Curing time varies depending on:
Avoid walking on the roof before it has fully cured.
Doing so may damage the surface.
Once cured, inspect the roof carefully.
Remove:
A smooth surface helps the final protective coating bond effectively.
The final flowcoat provides:
Roll the topcoat evenly across the roof.
Allow it to cure completely before exposing the roof to heavy use or foot traffic.
Many installation problems occur because of simple mistakes.
Fibreglass roofing should only be installed when the roof is completely dry.
Rain and moisture prevent proper adhesion.
Adding too much or too little catalyst affects curing.
Always measure accurately.
Dust, dirt, and loose materials reduce adhesion.
Clean the surface thoroughly before beginning.
Air pockets weaken the finished roof.
Always use laminating rollers to remove trapped air.
Applying inconsistent amounts of resin creates weak areas.
Maintain a consistent coating across the roof.
Yes, experienced DIY enthusiasts can successfully install small fibreglass roofs such as sheds or small garages.
However, larger roofing projects require skill and experience.
Professional roofing contractors understand curing times, weather conditions, expansion joints, and finishing techniques that ensure long-lasting performance.
For homeowners seeking guaranteed workmanship, companies such as S. Tomic Roofing LTD provide professional fibreglass roofing installations that meet industry standards.
A quality fibreglass roof typically lasts between 25 and 40 years.
Its lifespan depends on:
Annual inspections help identify small issues before they become expensive repairs.
Fibreglass roofing requires very little maintenance.
To keep it performing at its best:
Simple maintenance can significantly extend the roof’s service life.
Fibreglass roofing offers several advantages over traditional felt roofing.
Unlike felt, fibreglass creates a completely seamless waterproof membrane.
It is far more resistant to splitting, lifting, and weather damage.
Although installation costs may be slightly higher, its longer lifespan and reduced maintenance often make it the better long-term investment.
Absolutely.
Fibreglass roofing provides excellent value because it combines strength, durability, weather resistance, and minimal maintenance.
For homeowners looking for a long-lasting flat roofing solution, fibreglass remains one of the best investments available.
Learning how to do fibreglass roofing gives you a better understanding of one of the UK’s most reliable flat roofing systems. Every stage, from preparing the roof deck to applying the final protective topcoat, plays an important role in creating a durable, waterproof finish.
While smaller projects may suit experienced DIY enthusiasts, larger installations are best left to professionals to ensure the roof performs effectively for decades. With proper installation and routine maintenance, a fibreglass roof offers exceptional value, making it an excellent choice for homes and commercial properties alike.
Yes. Fibreglass roofing is suitable for garages, extensions, balconies, dormers, porches, garden rooms, and many commercial flat roofs, provided the roof deck is structurally sound.
Dry weather with moderate temperatures is ideal. Rain, frost, or excessive humidity can affect resin curing and reduce the quality of the installation.
Yes. Minor cracks, chips, and localised damage can usually be repaired using matching fibreglass matting and resin without replacing the entire roof.
Very little. Cleaning debris, keeping gutters clear, and carrying out an annual inspection are usually enough to maintain the roof’s performance.
Both systems perform well, but fibreglass roofing offers a harder surface, seamless finish, and greater impact resistance, making it an excellent choice for many flat roofing applications.
Copyright © 2025 S. Tomic Roofing Ltd
SEO by BRANDIX SOFT