AS 4654: External above-ground waterproofing membranes
AS 4654 is the Australian standard for external above-ground waterproofing. Part 1 covers materials, Part 2 covers design and installation. NCC H2D8 DTS path.
Ask Chalkline about this →AS 4654 is the two-part Australian standard for external waterproofing membranes on above-ground surfaces such as flat roofs, balconies, decks, planter boxes, and landscaped areas above habitable spaces. Part 1 (AS 4654.1:2012) sets the material requirements: composition, durability, UV resistance, and fitness-for-purpose testing. Part 2 (AS 4654.2:2012) sets the design and installation requirements: substrate preparation, falls, upstands, terminations, junction detailing, and inspection. Both parts were published September 2012 and remain current (verified 2026-05-13, Standards Australia).
Also known as: AS 4654.1, AS 4654.2.
Category: Waterproofing.
NCC reference
NCC 2022 Volume Two clause H2D8 (External waterproofing) is the deemed-to-satisfy path for external waterproofing systems on Class 1 and Class 10 buildings. H2D8(1) requires that membranes comply with AS 4654.1 and that the design and installation comply with AS 4654.2 (verified 2026-05-13, ABCB NCC Part H2). The DTS applies to flat roofs, roof terraces, balconies, and similar horizontal surfaces above internal building spaces.
Key prescriptive numbers
The two numbers that drive site failures on residential flat roofs and balconies:
| Item | AS 4654.2 requirement |
|---|---|
| Minimum fall | 1:100 (1%) across the membrane surface to drainage points. Practical recommendation for liquid-applied systems is 1:80 to absorb construction tolerance. |
| Minimum upstand | 150 mm above the finished surface at parapets, walls, and penetrations (Appendix A). |
Scope boundaries
AS 4654 does not cover sanitary plumbing or stormwater drainage downstream of the outlet (that sits under AS/NZS 3500.3), wet-area waterproofing inside the building (covered by AS 3740), or below-ground tanking (covered by manufacturer specification and AS 4858 for liquid-applied internal systems). The handoff between AS 4654 and AS/NZS 3500.3 is the membrane-side detailing of the waste outlet: AS 4654 governs the upstand, clamp, and flashing; AS/NZS 3500.3 governs the downpipe sized for the discharge.
Last updated: 2026-05-13. Verified: 2026-05-13.