Single Ply Roofing - what do you need to know?

Single ply roofing systems consist of a single layer or “ply” of material that acts as a waterproof barrier. Lightweight, flexible roofing membranes are engineered to be structurally durable and easily installed. They protect against rain, wind and UV – for a long lasting, flexible and highly convenient roofing solution.

Why consider single ply roofing?

Single ply roofing stands out for its simplicity, versatility and ease of installation. Traditional roofing usually has multiple layers, adding weight to a structure. Single ply systems are large sheets, 1 – 2mm thick, that are rolled into place, then glued or mechanically fastened to the roof.

Lightweight membranes are adaptable to a variety of roof shapes, gradients and installation methods, furthermore they’re suitable for refurbishments and roof replacements.

Single ply systems excel on low slope flat roofs and are designed with energy efficiency in mind, reflective surfaces reduce heat absorption, regulating temperatures and reducing costs.

Different types of single ply roofing membranes

TPO – Thermoplastic Polyolefin

White or light coloured, TPO reflects sunlight and can reduce cooling costs in warm climates, making it the most energy efficient solution.

TPO membranes are heat weldable, meaning seams are fused using hot air to create a sealed waterproof bond.

Thermoplastic single ply is prone to tearing in extreme weather, and has a shorter lifespan than other options if exposed to debris and strong winds.

When to choose a TPO membrane:

When energy savings are needed in hot climates

Low risk of seam failure is a priority

Sustainable building projects

PVC – Polyvinyl Chloride

PVC roofing is highly puncture and chemical resistant. It’s a strong choice for industrial sites and where roofs are exposed to harsh chemicals.

Polyvinyl chloride systems come in rolls that are thinner than EPDM, for easy handling and installation. These sheets are heat welded at the seams for secure bonding and waterproofing.

However, there are environmental concerns about chemicals produced during manufacturing PVC. PVC systems can be durable and long lasting, however, potentially offsetting environmental impact in the long run.

When to choose PVC:

When watertightness and durability are priorities over cost

Facilities with exposure to chemicals and oils

When meeting “cool roof” requirements

EPDM – Ethylene Propylene Diene Monomer

Referred to as “rubber roofing” EPDM usually comes in black. It’s highly flexible, and resistant to cracking in locations with high temperature variation, as well as UV radiation and weathering. Due to its dark colouring it can absorb heat and contribute to heat gain in your building.

Often installed with adhesive, as mechanical fasteners create a risk of leaks. EPDM systems are glued or taped at the seams, meaning regular maintenance is important to ensure longevity. Of the 3 systems EPDM is the easiest to repair.

EPDM solutions are best suited for:

Projects where budget is a top priority

Cold climates where high flexibility is needed

Projects which need a long product life proven solution

Installation Methods

Single ply membranes can be installed in 3 main ways:

Fully adhered – the most common installation method. Membrane is glued directly to the insulation or roof deck, creating a tight wind resistance finish. Fully adhered installation is used for installation on cementitious structures.

Adhering the membrane can take longer than other installation methods but has the lowest risk of leaking, and provides the best wind uplift ratings.

Mechanically fastened – fasteners and plates secure single ply membranes along seams, this means the membrane can be easily removed if needed.

For metal and timber structures, fastened systems are susceptible to “fluttering” in high wind and are most prone to leaks.

Ballasted – in a ballasted system, single ply is held in place with a layer of gravel, weighing the membrane down onto the roof.

An uncomplicated installation system, quick to install and easily maintained. Ballasted installation adds a lot of weight to the roof, so is unsuitable for certain installations.

Longevity and maintenance

When installed properly a single ply roof can provide a lifetime of at least 20 -30 years.

Thermoplastic membranes may be susceptible to puncture, so regular maintenance is essential to ensure longevity. Single ply roofs should be regularly inspected for punctures, loose seams and debris, with prompt repairs to any damage.

Improper installation can lead to seam separations and water permeability. Hiring an experienced team is necessary to ensure single ply systems meet their performance and longevity potential.

What to consider?

Finally, when selecting the correct solution for your project it’s important to think about:

Climate – light coloured membranes reflect heat for hot climates, while dark membranes can insulate in colder regions.

Building use – facilities with chemical exposure could require PVC for its chemical resistance and durability.

Budget vs longevity – higher upfront cost than some traditional roofing systems, but single ply can provide longer service life and require less maintenance, potentially costing less in the long run.

Installer expertise – skill of installation team can have an effect on the service life of the system, with poorly installed systems being more susceptible to water ingress and deterioration.

Environmental impact – PVC membranes have environmental concerns. With high chlorine content and potential to release harsh chemicals during the manufacturing process and when exposed to fire.

Repairs – repairing a single ply roofing system can sometimes involve full replacement, with tears being difficult to patch.

Traffic – you should avoid walking on a single ply roof when possible.

Conclusion

The unique combination of lightweight materials, easy installation and long term durability make single ply roofing a viable solution for a range of building projects.

With a choice of TPO, PVC and EPDM as well as a range of installation methods, there’s a single ply solution that works for almost all applications.

These systems can provide decades of protection, with rapid installation times, and minimal maintenance, keeping buildings dry and energy efficient for years to come.

Single Ply Roofing – what do you need to know?