Flat Roofing Systems Explained
The modern installation methods provide structures with long-lasting protection. Many of these systems now offer lifespans of 20 years or more when installed correctly.
They can be adapted to fit the requirements of a building, whether it’s a domestic or commercial property.
There are several different flat roofing systems used across the UK, each with its own advantages. Some of the main options include:
- GRP fibreglass roofing
- Single ply roofing
- EPDM rubber roofing
- Liquid-applied roofing
- Felt roofing
Each is designed to suit different types of buildings, budgets and performance requirements. They can often work with solar panels, especially on new builds and commercial units, as long as the roof is in good condition and properly installed.
GRP roofing
What is GRP roofing?
GRP fibreglass roofs have become one of the most popular options for modern flat roofs, especially on extensions and garages.
It combines a strong fibreglass matting with a specialist resin to create a seamless waterproof surface. It’s durable, lightweight and flexible, and can be moulded to almost any roof shape.
Unlike some traditional roofing systems, GRP roofing forms one continuous layer across the roof. Because there are no joints or overlaps, there’s very little opportunity for water to get in.
GRP fibreglass roofing is a popular option across both domestic and commercial projects, and is one of the systems we regularly install at Roof Care 365.
Why people choose GRP roofing
The main benefits include:
- Long lifespan of around 20–40 years
- Strong and durable surface
- Low maintenance requirements
- Modern appearance
- UV and weather resistant
- Suitable for complex roof shapes and detailing
Disadvantages of GRP roofing
- Higher upfront cost compared to felt
- Installation can take longer in poor weather
- Poor workmanship can lead to cracking or defects
- Less suitable for very large commercial roofs
Popular uses for GRP roofing
- House extensions
- Small commercial properties
- Garage roofs
- Balconies
- Dormers
- Garden rooms
- Walkways
Single ply roofing
What is single ply roofing?
Single-ply roofing uses a flexible membrane installed in large sheets across the roof. Depending on the system, it can be mechanically fixed or fully adhered to the roof deck, with the seams heat-welded together for a watertight finish.
Because it’s lightweight and can cover large areas efficiently, single-ply roofing is particularly well suited for commercial roof installations, although it can also be used on some domestic flat roofs.
Why people choose single ply roofing
- Fast installation process
- Suitable for large roof areas
- Long lifespan
- UV resistant
- Lightweight
Disadvantages of single ply roofing
- Can be punctured by heavy foot traffic
- Requires specialist installation
- Material quality can vary
- Usually more suitable for commercial rather than smaller domestic projects
Popular uses for single ply roofing
- Commercial buildings
- Warehouses
- Schools
- Retail units
- Industrial properties
- Large flat roof areas
- New build developments
EPDM rubber roofing
What is EPDM roofing?
EPDM is a synthetic rubber roofing membrane commonly used on flat and low-pitched roofs. Although technically a type of single-ply roofing, it’s often considered separately because it uses a rubber membrane rather than the PVC-style systems commonly found on larger commercial roofs.
The membrane is available in large sheets, helping to reduce the number of seams required across the roof. It’s flexible, resistant to UV exposure and can accommodate movement caused by changing temperatures.
It can be used on both domestic and commercial properties, although it is particularly popular for garages, extensions and smaller flat roof areas.
Why people choose EPDM roofing
- Long expected lifespan
- Flexible material
- Good resistance to UV and weathering
- Relatively low maintenance
- Lightweight
- Large sheets can reduce the number of seams
- Suitable for domestic and commercial roofs
Disadvantages of EPDM roofing
- Can be punctured by sharp objects or heavy foot traffic
- Detailing around roof edges and penetrations needs careful installation
- The appearance may not suit every property
- Professional installation is important to achieve reliable seams and detailing
Popular uses for EPDM roofing
- House extensions
- Garage roofs
- Garden rooms
- Outbuildings
- Small commercial roofs
- Modular buildings
- Green and solar roof systems
Liquid-applied roofing
What is liquid roofing?
This type uses a waterproof coating that is applied directly to the roof surface before curing to form a continuous membrane.
Because the material is applied as a liquid, it can work particularly well around awkward roof shapes, joints, outlets and other areas where detailing can be more complicated. The finished membrane is seamless, which reduces the number of joints where water could potentially enter.
These systems can be used for new roofs, but they are also commonly used when refurbishing or waterproofing an existing roof.
Why people choose liquid roofing
- Seamless waterproof finish
- Suitable for complicated roof details
- Can be used for new roofs and refurbishment
- Works with a range of existing roof surfaces
- Flexible once cured
- Useful for roofs with multiple penetrations or awkward shapes
Disadvantages of liquid roofing
- The existing surface needs to be properly prepared
- Performance varies between different products and systems
- Installation conditions can affect some products
- Specialist installation may be required
- Cost can vary considerably depending on the roof and system specified
Popular uses for liquid roofing
- Commercial flat roofs
- Roof refurbishment
- Complex roof shapes
- Roofs with multiple penetrations
- Balconies and terraces
- Existing felt or asphalt roofs
- Localised waterproofing projects
Felt roofing
What is felt roofing?
One of the more traditional flat roofing systems, felt roofing is still widely used across the UK today.
Modern felt roof systems are much more advanced than older versions, designed to provide reliable waterproof protection at a more cost-effective price.
Most modern systems are installed using multiple layers of bitumen-based felt, often applied using a torch-on installation method. The upper layer is often finished with a mineral surface, which helps protect the roof covering from weathering and UV exposure.”
It’s still widely used because it offers a reliable and cost-effective option for both homes and commercial buildings. But while it’s relatively simple to repair, it has a shorter lifespan than the other types of flat roofs.
Why people choose felt roofing
- Lower upfront costs
- Reliable waterproofing
- Easy to repair
- Suitable for many property types
- Proven roofing system
- Good lifespan when properly maintained
Disadvantages of felt roofing
- Shorter lifespan than some alternatives
- More maintenance may be required over time
- Seams can weaken as the roof ages
- Less modern appearance
Popular uses for felt roofing
- Garages
- Sheds
- Extensions
- Smaller flat roofs
- Budget-conscious projects
- Outbuildings
Which flat roof system lasts the longest?
In the majority of cases, the lifespan of a flat roof depends on the materials used, as well as the quality of the installation and how well it’s maintained over time.
Here is a general comparison of the most common systems:
| Roofing System | Typical Lifespan | Best For | Main Advantage |
|---|---|---|---|
| GRP | 20-40 years | Domestic roofs | Seamless waterproof finish |
| Single Ply | 25-40 years | Commercial roofs | Lightweight and efficient |
| Felt | 15-25 years | Smaller/budget projects | Cost-effective |
| EPDM | 30-50+ years | Domestic and commercial roofs | Flexible and long-lasting |
| Liquid Roofing | Varies by system | Refurbishment/complex roofs | Seamless around details |
These figures are a general guide only. Ultimately, the best system will depend on the type of property. For example, GRP is often well suited to smaller domestic roofs, while single ply is commonly used across larger commercial roof areas. Felt can offer a more cost-effective option for a wide range of projects.
The success of any flat roof also comes down to drainage. Even though they look flat, they’re always built with a slight fall so rainwater naturally runs towards gutters or outlets. If that fall isn’t correct, even the best system will eventually struggle.
It also needs to cope with movement and temperature changes as it expands in heat and contracts in cold weather. The best systems are designed to flex slightly rather than crack or split under pressure.
Why professional flat roof installation matters
These systems rely heavily on proper installation for effective drainage, waterproofing and long-term performance. In fact, one of the main causes of leaks is often poor installation.
Without proper roofing knowledge and expertise, flat roofs can fail over time, even if the highest-quality materials are used. Keeping outlets and the roof surface clear is part of this, which is where regular roof cleaning can help.
A professional installation will ensure:
- Correct roof falls for drainage
- Proper waterproof detailing
- Strong edge sealing
- Suitable ventilation
- High-quality workmanship
- Long-term reliability
Our experienced roofing specialists will make sure your roof is installed correctly, helping to avoid costly repairs and extend its lifespan.
As members of the Confederation of Roofing Contractors (CORC), we provide a 10-year insurance-backed warranty on all new roofs.
Flat roofing services for Somerset & the South West
Roof Care 365 provides professional flat roofing services across Somerset and the South West for both domestic and commercial properties.
Our team installs and repairs a wide range of flat roofing systems, including:
- GRP fibreglass roofing
- Single ply roofing
- Felt roofing
- Commercial flat roofing systems
- Flat roof repairs and replacements
We work across Somerset and surrounding areas including Taunton, Bridgwater, Yeovil, Weston-super-Mare, Exeter and beyond. If you’re not sure which flat roofing system is best suited to your building, we’re more than happy to provide advice.
We also provide a 24/7 emergency call-out service for roof repairs, so you know you’re in safe hands whenever an unexpected issue arises. Contact us today to let us know your project’s requirements.
Flat roofing FAQs
How long does a flat roof last?
The lifespan of a flat roof mainly depends on the material used as well as the quality of the installation. GRP roofing can often last 20–40 years, single ply systems can exceed 30 years, while felt roofing typically lasts around 15–25 years.
Is GRP roofing better than felt?
GRP roofing can be a good choice for many domestic flat roofs, particularly extensions, garages and other smaller roof areas. It generally offers a longer lifespan and a more seamless finish than felt roofing.
What is the cheapest flat roofing option?
Felt roofing is usually one of the most affordable flat roofing systems available. However, it tends to have a shorter lifespan and a more traditional appearance than systems such as GRP.
Can flat roofs be repaired instead of replaced?
Yes, many flat roofs can be repaired depending on the extent of the damage. Minor leaks, cracks or damaged sections can often be repaired without needing a full replacement. We offer emergency roof repairs under our roof care plans.
How much does flat roofing installation cost?
The initial cost of installation will depend on several factors, including the roofing system chosen, roof size, access requirements and the condition of the existing roof. Please contact us for a quote.