Single Ply Roofing Systems: TPO, PVC, and EPDM Explained

Single ply roofing refers to a range of factory-manufactured membrane systems installed as a single layer of waterproofing. They're the dominant system for large commercial and industrial flat roofs, and they've been growing in residential and small commercial use too.

TPO (Thermoplastic Polyolefin)

TPO is the most widely specified single ply system for commercial roofing in the UK. Seams are heat-welded, creating a joint stronger than the membrane itself. It's light-coloured (reflective), which can reduce cooling loads on commercial buildings. Very durable and recyclable at end of life.

PVC (Polyvinyl Chloride)

PVC single ply was the dominant system before TPO became popular. Like TPO, it's heat-welded. PVC membranes are flexible and easy to install around complex details. Some environmental concerns exist around plasticisers — TPO is generally considered more environmentally friendly.

EPDM (Ethylene Propylene Diene Monomer)

EPDM is the dominant single ply for domestic and small commercial roofs in the UK. It's available in large sheets, minimising joins. Seams are bonded with adhesive or tape rather than heat-welded. Less suited to very large commercial roofs than TPO but excellent for anything under approximately 500m².

Installation Methods

Single ply membranes can be fully bonded (glued to the insulation), mechanically fastened (screwed through the deck), or ballasted (held down by stones or paving). Each method has different performance characteristics and suitability for different applications.