Single ply roofing is becoming the go-to choice for modern flat and low-pitch roofs, but what actually is it, and why are so many projects choosing it?
If you’re planning a new build, extension or refurbishment, knowing what single ply roofing is (and what it isn’t) can help you make a smarter, longer-lasting decision.
Here, we break down how single-ply roofing works, the different types of membranes, its key benefits, where it’s best used, and what you need to keep in mind before you commit.
What is single ply roofing?
Single ply roofing is a waterproof roof that’s made from a flexible sheet membrane, which is installed in a single layer. It’s created for flat and low-pitched roofs where roof tiles aren’t practical.
The membrane is installed as part of the complete roof build, it sits above the insulation and a vapour control layer (VCL) to help stop heat loss and condensation, in line with UK Building Regulations.
In other words:
- The single ply membrane keeps the water out
- The insulation keeps the heat in
- The vapour control layer helps prevent condensation
Together, you get a modern, high-performance flat roof system.
Types of single ply roofing membranes
Single ply roofs are made up of three different types of membranes: PVC, TPO, or EPDM. These are the different types:
PVC (Polyvinyl Chloride)
PVC is probably the most common membrane used, especially on larger commercial and industrial roofs.
The main benefits:
- Flexible: Gooffor use around rooflights, upstands and penetrations.
- Seams that can be heat welded: Sheets are hot air welded to create strong, watertight seam.
- Widely available: It’s been used for a long time, and plenty of people are trained to install these roofs.
Things to consider:
- PVC membranes contain plasticisers to keep them flexible. Over a long time, plasticiser migration can affect performance if the system isn’t well designed.
- PVC can be incompatible with certain materials, like bitumen and some types of insulation. In this case, separation layers are used.
TPO (Thermoplastic Olefin)
TPO is becoming a popular choice, especially for those who want to focus on their environmental impact with construction.
The main benefits
- Heat-reflective finishes: Often supplied in light colours that help reduce heat building up on the roof’s surface.
- No added plasticisers: TPO membranes use a polymer formulation for flexibility rather than traditional plasticisers.
- Potentially recyclable: Deemed the environmentally preferred choice compared with older technologies, as there is potential to be recycled.
EPDM (Ethylene Propylene Diene Monomer)
EPDM is a synthetic rubber membrane that’s very popular on domestic flat roofs, as well as smaller commercial projects.
The main benefits
- Durable: EPDM has a long life and excellent resistance to UV and weathering.
- Low maintenance: Once installed, it needs minimal attention, just routine inspections and keeping outlets clear.
- Large sheet sizes: Systems are sometimes supplied in big, made-to-measure sheets that cover small roofs in a single piece, so there are no seams to contend with.
Benefits of single ply roofing
Single ply roofing has become a popular choice, simply because there are numerous benefits to it. Here are the things you should know:
Performance and durability
With over 50 years of proven performance, they are chosen for their long-lasting nature and are able to withstand UV, ozone, and severe weather conditions.
Longevity
The materials used are expected to last between 20 and 30 years.
Waterproofing
A seamless, watertight barrier is made which reduces the chance of leaks and water damage.
Fire rating and strength
Single ply systems are typically Class A fire-rated and have high tensile strength.
Wind resistance
When applied to a firm fixed substrate, they have excellent wind uplift resistance.
Quick installation
Installation is typically quick and easy. With large sheets or rolls, they’re quickly applied, labour costs are reduced, and you get minimal disruption within the building.
Lightweight
Single-ply roofs are relatively lighter when compared with other types of roofs, which reduces the loading of the structure.
Cost-effective
Single ply roofing is often deemed the cost-effective choice. Long-term costs are down to the material’s durability and lower maintenance costs.
Energy savings
The materials are often made in white or reflective surfaces, which help maintain a stable indoor temperature, cutting a building’s cooling costs. Or you can use a black membrane to help with heat retention.
Versatility
Suitable for various roof designs, including flat and low-slope roofs. They can also be used on new buildings or for replacement projects.
Thermal performance
Ballasted systems stop thermal bridging as no fasteners are needed, which makes them sustainable and energy efficient.
Common applications of single ply roofing
Commercial and industrial buildings
Warehouses, offices, schools, healthcare and retail units often use single ply roofing where speed, weight and cost are key.
Residential and mixed-use projects
These are ideal for flat roof extensions, apartment blocks, podium decks, and common roof areas where a clean, tidy, and contemporary finish is needed.
Refurbishments and overlays
Single ply membranes can sometimes be installed over existing flat roofs, improving waterproofing and thermal performance with minimal disruption.
Specialist roofs
Single ply roofs can also be used on green roofs, plant decks, roofs with solar PV and terraces, where the membranes need to integrate with multiple layers and penetrations.
Design and installation considerations
Not only do you have to make a choice on the type of membrane that you’d like to install, but there are other aspects that need to be considered, too. Here’s what you need to think about:
- Roof build-up and substrate: The structural deck needs to be sound and suitable. Correct falls and drainage design are needed to avoid standing water.
- Fixing methods: Single ply membranes can be mechanically fixed, fully adhered or ballasted. The right choice depends on wind uplift, insulation type, access and budget.
- Detailing and penetrations: Corners, upstands, outlets, rooflights, and services need careful detailing. Most performance problems are down to the details, not the main roof.
- Regulations and standards: Roofs must meet UK requirements for fire, thermal performance and condensation control. Pops Facades pride themselves on their expert knowledge of what is expected from these types of jobs.
Lifespan, maintenance and warranties
Typical lifespan
A well-designed and correctly installed single ply roof can expect to last between 20 and 30+ years, depending on the membrane type and thickness.
Maintenance needs
Routine inspections are suggested, particularly after severe weather. Clearing debris from outlets and checking for damage helps to maximise lifespan and keep your warranties valid.
Warranties and guarantees
Many systems come with manufacturer-backed warranties that cover your materials and sometimes labour. Use a reputable installer to help get this put in place for your single ply roof.
What is single ply roofing? It it right for you?
Single ply roofing should be a strong contender if you want a lightweight, durable and cost-effective solution for a flat or low-slope roof. It performs well on everything from warehouses to offices and home extensions.
If you want fast installation, reliable waterproofing and good long-term value, it’s definitely a contender.
But it isn’t a one-size-fits-all answer. The right choice of membrane, fixing method and roof build-up depends on how the roof is going to be used, the existing structure, and, of course, your budget. The best results come from a properly designed system that’s installed by an experienced team who know and understands the full building envelope, not just the roof covering.
Talk to Pops Facades about your single ply roofing
At Pops Facades, we can help explain what is single ply roofing and whether it’s the right option for your project, and if it is, we can design and install a system that’s built to last.
Get in touch with Pops Facades to discuss your project, request a roof survey or ask for a no-obligation quotation today.
