A roof upstand is a vertical edge or raised wall at the side or end of a flat or gently sloping roof, intended to retain water and to neatly finish edge details such as parapet walls, roof lights, roof penetrations or roof rims. The upstand forms the transition between the roof surface and an adjoining element such as a façade, a roof light or a roof edge.
Function of a roof upstand
A roof upstand serves several functions at once:
- Water retention — prevents rainwater from leaving the roof surface where it shouldn’t
- Connection detail — provides a vertical surface against which the roofing membrane can be turned up and bonded
- Protection — protects vulnerable connections from wind, water build-up and leakage
- Aesthetics — conceals the roof build-up and provides a neat roof edge
Types of roof upstands
- Wall upstand — the upstand along a façade, often combined with lead flashings or an aluminium edge trim
- Edge upstand — the upstand along the perimeter of a flat roof, usually capped with a coping or trim
- Penetration upstand — a raised rim around a roof light, roof window or roof penetration (at least 150 mm above the roof surface per typical standards)
- Prefabricated upstand — ready-made upstand of timber, plywood or plastic for roof lights and windows
Application and execution
In a well-detailed roof upstand the membrane (bitumen, EPDM or single-ply) is taken up at least 150 mm above the roof surface and finished at the top with a capping profile or lead flashing. The upstand itself is usually built from timber framing, plywood or a prefab element. At the top, a roof trim or wall capping is fitted to drain rainwater away.
Related terms
- Roof edge trim
- Roof covering
- Roof light
- Flat roof
- Roof penetration
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