Single ply roofing uses one flexible layer of synthetic membrane to waterproof a flat or low-pitched roof. Instead of building up several layers of bitumen felt, the membrane is laid in large sheets and joined with taped or heat-welded seams, giving a lightweight covering with very few joints.
We install three types: EPDM, a synthetic rubber; TPO; and PVC. All three suit flat roofs on rear extensions, dormers, garages and bays, as well as larger commercial roofs. Which one is right depends on the size and shape of your roof, how many details it must work around, such as rooflights, soil pipes, parapets and abutments, and whether insulation is being added at the same time.
EPDM, TPO and PVC compared
- EPDM is a synthetic rubber membrane, often supplied as one sheet cut to fit the whole roof on smaller jobs. It is bonded to the deck with adhesive and laid without naked flames, a sensible choice where heat would be a risk near timber or neighbouring properties.
- TPO is a thermoplastic membrane whose seams are welded with hot air, so the joins become part of the sheet. It is a flexible option for roofs with lots of laps and junctions.
- PVC is also hot-air welded and forms easily around complex details, with pre-made corners and pipe collars available. It must be kept apart from bitumen, so an overlay needs a separation layer.
None of these is the answer for every roof. We explain the trade-offs for yours, covering detailing, foot traffic, appearance and fixing method, in the quote.
What the work involves
A membrane is only as good as what lies underneath it. We strip the old covering, check the deck and replace any boards that are rotten or delaminated. Where insulation is being upgraded, the usual approach is a warm roof: a vapour control layer on the deck, rigid insulation boards above, then the membrane on top.
Edges and upstands take as much care as the main area. Membranes are dressed up walls beneath flashings, finished with trims at eaves and verges, and sealed around outlets and rooflights. The roof also needs a proper fall so water runs to the gutter or outlet instead of sitting in puddles.
Flat roofs on Newcastle homes
Flat roofs are common on the rear offshoots of terraced houses and Tyneside flats, on dormers added to older properties, and on garages and extensions throughout the city's suburbs. Many were originally felted, and plenty of those coverings are now cracking and blistering.
Wind is a real consideration here, particularly near the coast and on exposed sites. Single ply membranes resist uplift through full adhesion, mechanical fasteners or ballast, with the fixing density increased around edges and corners where suction is strongest. Near the sea we also pay attention to trims and fasteners, choosing materials that stand up to salt air.
Building regulations and insulation
Replacing the covering of a flat roof counts as renovating it, and when a large enough area is involved building regulations normally expect insulation to be brought up to current standards where that is practical. Extra insulation raises the roof level, which affects upstands, door thresholds and window sills, so we look at this before quoting.
We can advise on what is likely to be needed and whether a building notice should be submitted, but the final decision rests with building control. If your extension roof doubles as a floor for a terrace or balcony above, that is a different design again, with loading and guarding to consider, and we will say so plainly rather than adapt a standard roof build-up.
