Modern Wet Area Finishes
A compliant pathway for modern floor finishes

NCC Volume Two

Area of NCC Requirements:

Part H4 – Health and Amenity

• H4P1 – Wet Areas
• H4D2 – Wet Areas
• H4D3 – Materials and Installation of Wet Area Components and Systems

The Challenge

Polished and burnished concrete floors are becoming increasingly popular in modern residential design. They provide a clean, seamless finish and are often selected where clients want a contemporary appearance, durable surface and integrated floor heating.

In this project, polished concrete was proposed within wet areas instead of a traditional tiled floor finish. The design also included hydronic heating within the floor build-up.

The challenge was that the NCC’s Deemed-to-Satisfy provisions for wet areas are generally based around conventional waterproofing and floor finish systems. A polished concrete finish does not always align neatly with the standard DTS pathway, particularly where the floor finish, heating system and waterproofing strategy need to work together as one complete system.

This raised important compliance questions around water resistance, moisture migration, waterproofing performance and long-term protection of the surrounding structure.

What This Means

The NCC does not simply require a particular surface finish to be used in wet areas. Instead, it requires the wet area to perform correctly.

This means the floor and wall systems must be designed to prevent water from causing damage to building elements, protect adjoining spaces from moisture, and maintain safe and healthy internal conditions over time.

When a non-traditional finish such as polished concrete is proposed, the main question is whether the entire floor system can manage moisture as effectively as a conventional DTS-compliant wet area system.

For this type of design, the assessment needs to consider more than the visible surface finish. It must also consider the waterproofing system, slab construction, floor falls, junctions, penetrations, heating elements, sealers and long-term durability of the completed wet area.

The Solution

A Performance Solution was prepared to assess whether the proposed polished concrete wet area floor system could satisfy the relevant NCC requirements.

The assessment considered:

• How water would be managed within the wet area under normal use
• Whether the floor system could prevent moisture migration into the slab and adjoining construction
• The interaction between the polished concrete finish, waterproofing layers and hydronic heating system
• The ability of the system to protect structural and surrounding building elements
• Long-term durability and resistance to moisture-related deterioration
• Whether the completed system could achieve an equivalent level of performance to a conventional DTS wet area system

Rather than assessing the polished concrete finish in isolation, the Performance Solution reviewed the wet area as a complete integrated system.

This allowed the proposed design to be considered based on its actual performance, rather than being rejected simply because it did not follow a traditional tiled finish pathway.

Why This Matters

The final assessment confirmed that the proposed polished concrete wet area system could satisfy the relevant NCC Performance Requirements for wet areas.

Although the design departed from a standard DTS approach, the performance-based assessment demonstrated that the floor system could provide appropriate moisture protection when supported by suitable detailing, waterproofing measures and construction controls.

This project highlights how Performance Solutions can support modern design choices in residential construction.

Non-traditional finishes, such as polished concrete, can provide strong architectural outcomes, but they must be assessed carefully to ensure they do not compromise waterproofing, durability or compliance.

With the right technical assessment, builders, designers and certifiers can proceed with confidence while still achieving the design intent of the project.

Considering non-traditional finishes in wet areas?
Reach out to our team for the solution.