Single Ply Membrane

What is single-ply membrane?

A single-ply membrane is a relatively thin sheet of flexible, durable, waterproof material that provides the vital final layer to your roofing system. As it can be laid in a single sheet and can be attached to almost any roof design, they are mostly used on large commercial buildings, so that an organisation can find a simple, single solution to fit their multiple roofing needs: factories, warehouses, stores and offices. There are many different types of membrane used in single-ply roofing, broadly divided into two categories: thermoplastic and elastomeric. Thermoplastic membranes respond to heat, softening allowing hot welding, for instance PVC (polyvinyl chloride). Elastomeric membranes are also suitable in the UK as they are not as sensitive to temperatures and are more weather resistant. They include Butyl rubber and EPDM.
Whether thermoplastic or elastomeric, single-ply membranes are made from synthetic polymers or natural rubber, often reinforced with glass fibre or polyester.

Single-ply membrane diagram

A diagram showing the layers of single-ply membrane roofing

Types of Single Ply Membrane roofing


Polyvinyl chloride or PVC is the most common material used in single ply membrane roofing in the UK, used in around 80% of our flat roofs. As it is thermoplastic, hot welding can be used to seal the seams of overlapping sheets, ensuring a uniformly waterproof covering. The life span varies from 20-40 years, depending on the composition of PVC, and at Just Flat Roofing we offer a 15 year guarantee. PVC is cheap and easy to install yet only partially recyclable.


Thermoplastic Polyolefin or TPO is very strong and even more resistant to damage, wear and tear than PVC, with an average life-expectancy of over 35 years. Unlike PVC, it requires a very clean, careful installation. Fortunately, at Just Flat Roofing, we can provide just that.
The latest version of TPO is TPE or Thermoplastic Polyolefin Elastomer. Although it is currently more expensive, the installation is less specialised as a wider range of heat can be used. It lasts even longer as small holes can be repaired using heat and the material is fully recyclable.


Polyiso Butylene or PIB is the most durable roofing material on the market, able to withstand and exceed half a century. It is fully recyclable and has low impact on the environment during manufacturing. It is the only membrane with a full life cycle assessment to ISO14040 with no significant impact to the environment and so may be considered to be the most environmentally friendly single ply membrane.

Benefits of single ply membrane

  • Quick to install
  • Easy to repair, modify and refurbish
  • Extrememly adaptable
  • Highly insulating and energy efficient
  • Various colour options
  • Suitable for eaves, verges and parapets

Flat Roofing Guarantees

Material Just Flat Roofing Guarantee Technical product guarantee backed by supplier Guarantee period
PVC 15-20 years
SIG Membrane 15-20 years
Rubber (EPDM) 15 years
Felt 10 years
GRP 15-20 years
Liquid 15-20 years

For roofing materials not covered here please contact us.
Disclaimer: We install quality flat roofs that will last for years, our guarantee is offered in good faith and covers failure of materials or installation. Guarantees are invalidated by customer misuse or improper care. Just Flat Roofing will always give proper advice that will need to be followed for the guarantee to be valid in the event of an issue.

Just Flat Roofing – Single-ply membrane flat roofs

Though single-ply membrane is fairly quick and easy to install, the wide range of types and methods of attachment available call for competent and experienced professionals. Single-ply membranes can be laid in one piece with pre-fabricated eaves and verge or in strips, joined by heat welding, proprietary solvent or adhesive tapes, depending on the membrane. There are no national standards, let alone international, and installation specifications vary not only with material but also with manufacturer. Just Flat Roofing operates in strict accordance with the manufacturers details, the British Board of Agreement (BBA) and WIMLAS. For example, we always lay sheets from the lowest point of the roof first, so that rainwater runs off lapped joints rather than seeping between sheets. An important precaution to take in the sunny north of England.

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