Unenclosed Shower

Secondary Floor Waste Alternatives

NCC 2022 Volume 2

Area of NCC Requirements:

• H4P1 – Wet Areas
• H4D2 – Wet Area Waterproofing
• AS 3740:2021 – Waterproofing of Domestic Wet Areas

The Challenge

Unenclosed, hobless showers are now a staple of modern bathroom design. But when these layouts include unenclosed showers, the Deemed-to-Satisfy (DTS) pathway often requires a secondary floor waste to manage any water that may travel beyond the immediate shower area.

In this project, the proposed bathroom design intentionally omitted the secondary waste. While aesthetically desirable, this created a compliance gap: the NCC requires evidence that moisture will still be controlled and that building elements remain protected over the life of the structure.

What This Really Means

When DTS provisions can’t be met, the NCC still allows the design—as long as it can be shown to perform to the same standard or better in terms of water containment, drainage, and long-term moisture protection.

The Solution

A performance solution was developed to demonstrate that the proposed bathroom layout could safely function with a single drainage point while still achieving the NCC’s moisture-management intent.

The assessment considered:

• How the bathroom’s geometry manages water movement
• Whether the layout adequately prevents water from migrating into dry areas
• The ability of the drainage system to collect and dispose of water effectively
• The robustness and continuity of the waterproofing strategy
• How the overall configuration aligns with the functional outcomes of AS 3740:2021

Rather than relying on prescriptive plumbing redundancy, the solution focused on how the entire wet area design functions as a system to contain and manage moisture during normal use.

Why This Matters

The final report confirmed that the design meets NCC 2022 performance requirements relating to wet areas and household moisture control. Despite departing from DTS provisions, the bathroom was shown to function safely, reliably, and in a way that protects both the structure and occupants.

This project is a strong example of how performance solutions allow modern bathroom design to evolve—without compromising compliance or practicality.

Need a something similar for your project? 

Reach out to our team for the solution.