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Connecting top plates

Figure 4: Top plate connections - Build 138

For buildings where the wall bracing has been designed to NZS 3604:2011 Timber-framed buildings, there are extra requirements for top plate connections in walls containing bracing elements. Paragraph 8.7.3.3 requires in line connections in top plates of walls containing bracing elements in single-storey buildings. Paragraph 8.7.3.4 requires top plates in walls containing bracing elements to be connected to external walls at right angles to it, either directly or through a framing member.  These connections need to achieve the stated capacity as detailed in the respective paragraphs.

Christchurch City Council building inspectors often encounter oversight to these requirements, especially for internal walls that contain bracing elements and are not directly connected to external walls at right angles. The requirement is commonly achieved by extending a continuous 140 x 35 extra top plate (ceiling plate) from along the top of the internal wall to over the external wall and then fixed to achieve the required capacity. Note: for walls containing more than 125 bracing units the connection will need to be to at least two external walls.

See the BRANZ Build 138 magazine article: Connecting top plates(external link) for further guidance.

For a building inspector to pass your building inspection the building work must be constructed as per the plans and specifications approved by the building consent including any cited Standards.

Safe trays under storage water heaters

The ‘Acceptable Solutions and Verification Methods for New Zealand Building Code Clause G12 Water Supplies(external link)’ was amended on the 1 January 2017. A notable change to this document can be found in G12/AS1 where there is now a requirement for safe trays under all storage water heaters complying with paragraph 5.2.3.

Paragraph 6.11.3 (a) was amended to remove the following exclusion for when a safe tray under storage water heaters is required - ‘where water could penetrate another household unit within the same building’. This paragraph now requires safe trays under all storage water heaters. Paragraph 5.2.3 was amended to include the following wording ‘Performance E3.3.2: states that; free water from accidental overflow from sanitary fixtures or sanitary appliances must be disposed of in a way that avoids loss of amenity or damage to household units or other property.' Paragraph 5.2.3 goes on to state ‘An acceptable method of preventing water damage is to locate a safe tray below the water tank (see Figure 4). The safe tray shall incorporate a drain with a minimum diameter of 40mm. Where the tank overflow discharges into the safe tray, the diameter of the safe tray drain shall be greater than the overflow pipe from the tank and comply with Paragraph 5.2.2.’

Currently, the previous version of these acceptable solutions is also effective but from the 31st May 2017 only this new version (3rd edition, amendment 10) of the acceptable solutions will be effective. This will apply to all building consent applications received from this date. The provision for a safe tray under storage water heaters will need to either comply with G12/AS1 or the application will need to demonstrate compliance with the building code as an alternative solution.

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