Forté Guidance to E3 Installations passed through councils

Requirements for achieving an Alternative Solution for E3 installations:

1. Durability & Assured Maintenance

2. Impervious

3. Overflow

4. Constructed in a way that prevents watersplash

1. Durability & Assured Maintenance

The durability Requirement for “Floor Coverings - Protective or Acoustic Coverings” is 5 years.

Forte’s Durability Evidence of Compliance

In-service history

Overlay Timber Flooring has been installed in Kitchens, Laundries, and WC’s for longer than any other building materials. Forté only supplies timber flooring with Polyurethane finishes. Additional in-service history evidence:

1. Matai timber flooring that has stood up well to splashes and occasional floods over 25 years. - SOURCE: BRANZ Article ‘E3/AS1 and wet area flooring’

2. Forte have supplied thousands of timber floors for the past 20 years which have been installed in kitchens and other Wet Areas without any issue at all (Note if a major flood occurs, the flooring may need to be sanded and recoated). As these are generally private residential homes, please enquire for a specific example if required.

Laboratory testing

Forté engaged SGS New Zealand Ltd (An IANZ accredited laboratory) to conduct independent testing on the passage of moisture for all Forté timber flooring products, and all have passed this test. Please enquire for a copy of the test report(s).

2. Impervious

Impervious is defined in the E3/AS1 Acceptable solution as “Impervious – that which does not allow the passage of moisture”. While performance clauses E3.3.3 and E3.3.5 require impervious surfaces around sanitary fixtures/appliances, there are no verification methods provided. Refer to page 11 of E3/AS1 which states “No specific methods have been adopted for verifying compliance with the Performance of NZBC E3”

The Objective (E3.1) and Functional (E3.2) requirement of E3 is to prevent illness/injury or damage through accumulation of moisture, or damage caused by free water penetration.

Forte’s Impervious Evidence of Compliance

As there are no verification methods provided to test for an impervious surface, Forté engaged SGS New Zealand Ltd (An IANZ accredited labora­tory) to conduct independent testing on the passage of moisture for all Forté timber flooring products, and all have passed the test. Please enquire for a copy of the test report(s).

Further to the above, the Acceptable Solution as per Comment under 3.1.1 of E3/AS1 states, “Other floor finishes may also be capable of satisfying the performance for impervious and easily cleaned, if installed in a manner that prevents gaps or cracks within the finish and at any parts of its perimeter that are exposed to water splash, and/or if the surface is sealed with a suitable durable coating.”

This sentence can be broken into three parts to aid in demonstrating compliance:

· Installed in a manner that prevents gaps or cracks within the finish

We recommend a minimum D3 durability class of PVA. The D3 durability class rating means “Interior areas with frequent long-term exposure to running or condensed water. Exterior areas not exposed to weather.” Refer to EN204 for more information

To ensure the flooring is installed in a manner that prevents gaps or cracks within the finish, our Forte Timber Flooring Overlay System Installation Guide must be followed. This system requires using a water-resistant PVA adhesive in all joints (both along the length of the plank and at the ends of planks) during installation in areas containing sanitary fixtures or sanitary appliances.

· Installed in a manner that prevents gaps or cracks at any parts of its perimeter that are exposed to watersplash

To ensure the flooring is installed in a manner that prevents gaps or cracks at any parts of its perimeter that are exposed to watersplash, the Timber Flooring Overlay System Installation Guide must be followed. This system requires using an acrylic-based flexible joint filler specialised for use with timber flooring. This is to be used to seal any parts of the perimeter and any fixed items within the area (ie floor to wall junction, kitchen waste pipes) that are exposed to water splash (including a minimum of 1.5m from all sanitary fixtures and sanitary appliances in open-plan rooms as per 3.1.1 of E3/AS1).

· Surface sealed with a suitable durable coating

All timber flooring from Forté comes factory-finished with durable polyurethane (not oil) coatings with at least four layers of coating.

Polyurethane finishes have had over 50 years of in-service history in kitchens and bathrooms in New Zealand residential and commercial buildings, and provided it is maintained as per ‘normal maintenance’ requirements of B2/AS1 2.1, a quality polyurethane finish would be classified as “a suitable, durable coating”.

3. Overflow

E3/AS1 2.0.1 states that overflow is required when “…accidental overflow could damage an adjoining household unit or other property”. When in effect, the overflow clause in E3/AS1 requires containment (coving of 75mm), as well as floor wastes (complying with NZBC G13).

As there are complications around the detailing of containment and floor wastes with Timber Flooring, we recommend the specifier adhere to the exemption under E3/AS1 2.0.2, which states “Household kitchen sinks and laundry tubs that have an integrated overflow with a minimum flow rate of 0.25 l/s do not require additional overflow provision…”

4. Constructed in a way that prevents water splash from penetrating behind linings or into concealed spaces (E3.3.6)

Forté has developed the Timber Overlay Flooring System Installation Guide, which requires the flooring to be glued to the substrate rather than ‘floated’ on top of the substrate and minimizes the natural movement of the timber.

This, combined with the joint filling requirements (as mentioned under the ‘Impervious’ point above), creates a well-designed system that is constructed in a way that prevents water splash from penetrating behind linings or into concealed spaces.

If you are currently struggling on a project and need immediate assistance in gaining compliance with council, contact your Forte area representative.