What is the minimum upstand height required for a single-ply roof?

The requirement of a 150mm waterproofing upstand is fundamental to reliable detailing.

However, working with building insurers and the residential sector, SPRA is aware of the requirement for unimpeded access to balconies and roof-level terraces in many designs.

In this situation only, the requirement has been reduced to 75mm at the opening, provided that the following conditions are met:

  • Rapid removal or rainwater across the width of the opening, by including a proprietary drainage channel in front.
  • The waterproof membrane extends 150mm height in the door reveal and roof/abutment wall.
  • The waterproof membrane flashing extends fully below the door frame bottom rail and is sealed.
  • A horizontal gap of minimum 10mm between frame front edge and drainage.


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