Preformed Flange Building Codes & Rules

- Preformed Flange Tools™ simplifies the National Construction Code (NCC) with interactive graphics, including deemed to comply & best practices.

≥ 25

Concrete Screeds

≥ 50

≥ 25

Sealant

≥ 25

Hob Upturn

or Parapet

AS 4654.2:2012, 2.11

Finished Level^{AS 4654.2:2012, 2.11}

Below Overflow Outlet
Design flow maintained

≥ 25

Fall

Membrane

Substrate

AS 4654.2:2012, 2.5.2

≥ 1 : 100^{AS 4654.2:2012, 2.5.2}

Fall to Drain

Screed

≥ 25

AS 4654.2:2012, 2.11

Location^{AS 4654.2:2012, 2.11}

Above finished level & in a visible location
Direct water away from building
Visible so blockages can be easily detected

Height of Overflow

≥ 25mm below top of Sill, or
Lowest opening height

Preformed Outlet

with Face Flange

Turn Membrane into Overflow

≥ 25

≥ 50

≥ 25

Foam

Expansion

Joint

≥ 5°

Fillet

AS 4654.2:2012, 2.5.2

≥ 1 : 100^{AS 4654.2:2012, 2.5.2}

Fall to Drain

Drip Groove

Floor System

Height of Overflow

≥ 25mm below top of Sill, or
Lowest opening height

Height of Overflow

≥ 25mm below top of Sill, or
Lowest opening height

≥ 5°

≥ 25

≥ 50

≥ 25

1 : 80

Perimeter Sealant Joint

Base of Parapet

Pipe Through Parapet

Membrane Height

Height varies with wind class^[1][2]
Terminate with flashing, reglet or at drip groove^[3][4]

Membrane Height RULES

NCC 2022 V1

All Building Classes

NCC 2022 F1D5 [2019 Table F1.4]

May 2023

NCC 2022 Vol 1, F1D5

AS 4654.2:2012, 2.8.1.1

AS 4654.2:2012, A

A roof, balcony, podium or similar horizontal surface part of a building must be provided with a waterproofing membrane^{NCC 2022 Vol 1, F1D5}
To AS 4654.1 & AS 4654.2
Unless is a deck or perforated or directly above ground
Measured from top of surface finish to height of membrane^{AS 4654.2:2012, 2.8.1.1}
Height sufficient to prevent wind-driven water entry
Varies depending on wind class & level of protection
Termination heights to AS 4654.2 2012, Table A1 are minimum & informative only^{AS 4654.2:2012, A}
Must be specified based on individual project wind classification

AS 4654.2:2012, 2.8.1.1

AS 4654.2:2012, A

AS 4654.2:2012, 2.8.1.3

AS 4654.2:2012, 2.8.2.1

Height varies with wind class^{AS 4654.2:2012, 2.8.1.1AS 4654.2:2012, A}
Terminate with flashing, reglet or at drip groove^{AS 4654.2:2012, 2.8.1.3AS 4654.2:2012, 2.8.2.1}