Floor finishes in sanitary areas such as bathrooms, toilets, laundries and kitchens must be impervious to moisture and easy to clean as required by New Zealand Building Code Clause E3 (Internal Moisture). This requirement helps prevent water penetration into adjoining units, reduce mould growth, and avoid structural damage.
Always check project-specific requirements against the latest Building Code provisions and Acceptable Solution E3/AS1. Some flooring solutions are not covered under E3/AS1 and will need an alternative solution to demonstrate compliance with Clause E3.
Protection against Accidental Overflow
Containment and floor wastes must be provided where accidental overflow from sanitary fixtures, such as toilets, urinals, bidets, baths, showers, sinks, or tubs, could cause damage to adjoining units or property. Kitchen sinks and laundry tubs with an approved integrated overflow are exempt from this requirement.
Under E3/AS1, sheet vinyl flooring is deemed impervious and meets the requirement for containment when edges are coved or sealed where they meet doorways and walls, or within 1.5 metres of a sanitary fixture.
Floor waste fittings must securely clamp the sheet vinyl and form a watertight seal between the vinyl and the waste fitting.
Protection against Watersplash
Sheet vinyl is considered an integrally waterproof sheet material and is acceptable as an impervious, easy-to-clean floor covering in areas exposed to watersplash from sanitary fixtures and appliances. This is provided all joints are sealed and edges are either sealed or coved. In open plan spaces, this extends to within 1.5 metres of any sanitary fixture or appliance.
Flooring outside E3/AS1 Scope
Other hard flooring types such as luxury vinyl tiles (LVT), laminates, European hardened timber, and engineered timber are not covered under E3/AS1. However, they can be shown to satisfy the requirements of Clause E3 through an alternative solution.
For these flooring types, the requirement for impervious is verified using moisture penetration testing to ISO 4760. In this test, flooring samples are assembled as they would be in actual installation. A dye solution is placed in a cylinder securely positioned at the centre of a T-joint, and the setup is left for 24 hours. The samples are then inspected for any penetration of the dye solution to the underside. The floor covering and its joints can be deemed impervious if no moisture passes through.
Independent ISO 4760 moisture penetration test reports for Belgotex LVTs, laminates, European hardened timber, and engineered timber are available on the website. Details on how each flooring range complies with E3 are also provided in the BPIR Disclosure documents.
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