Membrane Skillion Roof Drainage

Where a skillion roof is finished with a waterproofing membrane, unique challenges exist for drainage in such small, confined spaces.

The Situation:
Skillion Roofs are defined as having the ceiling and roof running parallel, often with a gap of 300mm or less between. When terminated onto a parapet or similar, designing-in drainage from the lowest point can become a challenge due to limited space.

Architects & engineers require more specialised solutions that don’t compromise the waterproofing integrity of their projects.

The existing solutions:
Commonly available existing solutions had not been designed to address these very tight spaces and are typically under‐engineered.

Our design‐led solution:
The design brief for our RDSE80 was quite clear:

  • Reduce the installed height to a minimum
  • Incorporate all the critical success features of New Zealand’s most specified Roof Drain, the Aquaknight RD100

With an overall installed height of just 102mm from membrane, RDSE80 leaves generous space to run horizontal DWV80 pipework within a skillion roof cavity.

Figure1: RDSE80 in overflow configuration, on 20mm substrate

The design and manufacturing integrity of all our products undergo extensive trials in our on‐site FlowLab* testing facility. The test environment allows us to chart peak-to-minimum flow rates, optimising outlet geometry for maximum efficiency.

The validation:
Firstly, Hydraulics Engineers are calling for precise, credible data to ensure compliance with the NZ building code. And for the first time, they have the rigour of our calibrated facility’s test‐data to incorporate into their calculations.

This in turn of course, eases the pathway to compliance with Council.

Released in 2016, there are thousands of installations throughout New Zealand. And as you might expect the RDSE80 is now being specified by New Zealand’s leading Waterproofing Membrane suppliers as part of their system.

For specification details of our RDSE80, including flow rate test results, simply visit:
https://www.aquaknight.co.nz/mco-hiflow-se80mm-2

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*FlowLab is the only calibrated flow‐testing facility in NZ and provides precise test data