What is single-ply membrane roofing, and is it right for you?

This article will examine the different types of single-ply membranes, their applications, costs, and the key factors influencing their performance – giving a clearer understanding of whether single-ply membrane roofing is the right fit for your property.

What is a single-ply membrane?

A single-ply membrane is a roofing material made from a single layer of flexible synthetic polymer or rubber. Its purpose is to protect and waterproof flat or low-slope roofs in residential and commercial buildings.

What are single-ply membranes used for?

Single-ply membranes are lightweight, easy to install, and ensure long-lasting building protection, making them popular for commercial and residential roofing applications.

Single-ply membranes are favoured for their durability and affordability, making them a top choice for both residential and commercial projects. They are known for their longevity and resilience against weathering. Moreover, they work well with green roof systems, aiding energy efficiency and environmental sustainability. 

How much does a single-ply membrane roof cost?

There is a significant price range for single-ply membranes, depending on the supplier; this can cost £12 at the lower end of the scale to upwards of £150 per square metre (m²). The typical labour for installing a membrane roof costs between £1,500 – £2,300 (+VAT), according to Checkatrade. 

The total roof cost for single-ply membrane installation typically varies based on 6 factors, including the roof size, the roof type, features like skylights or pipe penetrations, the type of single-ply membrane, the location and the labour cost. 

Choosing a membrane from a reputable manufacturer with a proven track record helps ensure product quality and reliability. Checking the warranty coverage provides assurance against defects and potential issues, offering peace of mind for your roofing membrane investment. For example, Alwitra, a leading single-ply membrane supplier, offers a 25-year guarantee and a 50-year service life, demonstrating the reliability of their products and reducing the need for repair or maintenance costs long term.

What are the single-ply roofing membrane types?

Two primary categories dominate the market due to their distinct material compositions and performance characteristics.

  1. Thermoplastic Membranes:
    • PVC (Polyvinyl Chloride): PVC membranes are renowned for their exceptional durability, flexibility, and resistance to various environmental stressors. They excel in climates with high UV exposure and fluctuating temperatures, making them popular for commercial and residential roofing projects. PVC membranes are often reinforced with polyester or fibreglass to increase longevity.
  • TPO (Thermoplastic Olefin): TPO membranes have gained popularity recently due to their energy efficiency, heat-reflective properties, and ease of installation. TPOs blend polypropylene and ethylene-propylene rubber; these membranes resist UV radiation, punctures, and tears. They are particularly well-suited for commercial buildings where durability due to frequent use is required.
  1. Thermoset Membranes:
    • EPDM (Ethylene Propylene Diene Monomer): EPDM membranes are known for their exceptional weather resistance, flexibility, and longevity. They are made from synthetic rubber polymers and can withstand extreme temperatures, UV exposure, and ozone degradation without compromising structural integrity. They are commonly used in residential and commercial roofing applications, including low-slope and green roofs.

Each type of single-ply roofing membrane offers unique advantages and is tailored to specific project requirements. While thermoplastic membranes like PVC and TPO have increased durability and energy efficiency, thermoset membranes like EPDM are known for their weather resistance. Ultimately, choosing these membranes depends on budget, climate conditions, building design, and performance expectations.

What are the other flat roofing membrane options?

There are 2 other common types of flat roofing membranes to be considered: 

Built-Up Roofing (BUR): BUR consists of multiple layers of bitumen alternated with reinforcing fabrics, finished with gravel or a reflective coating. While BUR is known for its waterproofing capabilities, it’s typically harder to install than single-ply membranes and incurs higher labour costs. 

Bitumen Membranes: Similar to BUR, bitumen uses modified asphalt with added polymers for enhanced elasticity and durability. It is typically applied in rolls with heat or adhesive. Bitumen membranes are known to be easy to repair, but they require a torch-down installation that could pose a potential fire risk. 

What factors can impact the performance of single-ply roofing? 

Here are the top 3 factors that can affect the performance of single-ply membrane roofing: 

  1. Maintenance: A single-ply roof requires regular maintenance, with inspections recommended once a year for both residential and commercial properties. These routine inspections catch minor issues like small tears or punctures before they become more extensive. Cleaning off debris, ensuring drainage is working correctly, and fixing any damage right away can help improve the performance of the single-ply membrane roof. 
  1. Colour: Lighter-coloured membranes reflect more sunlight and heat, resulting in less thermal stress and reduced temperature fluctuations. Darker membrane colours typically absorb more heat, which causes more significant thermal expansion and contraction. This increased movement can lead to more wear and tear on the roofing material, potentially shortening the lifespan of the single-ply roof. 

Consider the colour of the membrane, and you can make a strategic choice that influences the performance and longevity of the roofing system.

  1. Durability: The weather in your area is a big deal in terms of how well your single-ply roof holds up. Whether it’s the temperature, strong winds, heavy rain, hail, or constant sun exposure, all these can wear down the roofing material over time. For example, the average yearly rainfall in the UK usually falls between 800 mm and 1,400 mm – picking a type of membrane, in this case using single-ply membranes that are excellent at waterproofing, increases your roof and building protection. 

Final thoughts 

Single-ply membranes offer ease of installation, are lightweight, and are energy efficient. With many types of single-ply membranes on the market, each with its advantages, you need to consider your property type, location and budget. It’s advisable to consult experts to find the best fit for your property or project.