At DraftRoom, we are often asked whether a window can be installed inside a shower area. The short answer is that it is not permitted under standard (Deemed-to-Satisfy) rules, but it can be achieved through a carefully prepared Performance Solution.

Key Points:

The NCC and AS3740:2021 prohibit windows within 1500 mm of a shower outlet under standard DTS rules.
A Performance Solution Report can allow it, provided it demonstrates compliance with NCC weatherproofing performance outcomes.
The client must engage and pay for the consultant preparing the report.
The report must be accepted by the building certifier before construction.
DraftRoom assists by identifying the requirement, advising on next steps, and integrating compliant details into the design.

Why It’s Typically Not Allowed

The National Construction Code (NCC) and AS3740:2021 – Waterproofing of Domestic Wet Areas prohibit windows within 1500 mm of the shower outlet under the Deemed-to-Satisfy (DTS) provisions.

This zone is considered the “shower splash area,” where constant exposure to water can lead to leaks through joints, frames, and seals. Over time, this can cause damage such as rot, mould, and deterioration of internal wall framing and finishes.

These rules exist to ensure long-term waterproofing performance and to protect both structure and occupants from moisture damage.

The Pathway to Approval: A Performance Solution

While the DTS provisions do not permit windows within the shower zone, the NCC allows flexibility through Performance Solutions.

This process allows a design to vary from the prescriptive rules if it can be shown to meet the Performance Requirements of the NCC, in this case H2P2 – Weatherproofing.

A Performance Solution Report must be prepared by a qualified external consultant, such as a waterproofing specialist or building performance expert.

Consultants are engaged directly by the client, with DraftRoom providing support, guidance, and coordination to ensure a smooth and well-managed process

What the Report Covers

A professional Performance Solution Report typically includes:

The scope of works and the area affected (for example, a window within the shower zone)
Reference to the relevant Performance Requirements and Functional Statements from the NCC
Specification of the materials, sealants, membranes, and installation methods
Evidence of product testing, manufacturer data sheets, and application details
A written expert judgment confirming that the design achieves equivalent waterproofing performance

The consultant’s findings usually confirm that when installed according to the proposed detailing, the window and waterproofing system satisfy the NCC’s performance outcomes for durability and moisture control.

Acceptance and Accountability

It is important to note that a Performance Solution Report does not automatically guarantee approval.

The final decision rests with the building certifier, who must be satisfied that the proposed design meets the required level of compliance.

All relevant parties, including the designer, builder, certifier, and owner, must accept the proposed solution before work proceeds.

This ensures everyone understands the design implications and accepts responsibility for the outcome.

DraftRoom’s Role

At DraftRoom, we ensure the process runs smoothly:

We identify when a proposed window design does not meet the NCC’s standard provisions.
We advise the client on the need to engage a qualified consultant to prepare a Performance Solution Report.
We update and document the design in accordance with the consultant’s recommendations, specifying all sealants, membranes, and materials.
We coordinate with the building certifier to ensure the report is reviewed and accepted before construction documentation is finalised.

This process ensures the design is buildable, compliant, and approved prior to construction.