NZS 3604
This document provides most of building code requirements for building a deck. Though the document is primarily for the construction of timber framed buildings, the first 7 sections are applicable for building deck. NZS3604 would probably account for around 80% of the design requirements for a deck. There is also specific details on floors for decks within the document.
The list below describes how the first seven section of this document relates to deck design. As mentioned below section 9 (Posts) is not relevant in NZS 3604.
1 Scope and interpretation
This section contains information on the definitions on the technical terms (e.g. bearers, joists, anchor piles etc) used construction for decks. There is also a diagram which helps explain the meaning of a loaded dimension, which is important for deck design.
2 General
This section contains information on the general aspects of using NZS3604 like:
- Dimensions
- Call sizes of timber
- Tolerances
- Timber used
- Fastening & fabrication
- Reinforcing steel
- Concrete
In addition to this there is a diagram showing protection of sub floor framing using DPC (Damp proof course)
3 Site Requirements
This section relates the soil type and other factors. There is also an important diagram relating to depth of post holes and sloping ground.
4 Durability
This section contains information on the durability of materials used in the construction of a deck. There is also a diagram detailing sheltered and exposed definitions of a deck. As all the decks designed using ROBO Deck designer have been designed using open slat decking, all the decks are considered to be exposed. For more information please go to the webpage on Durability.
5 Bracing Design
This section is a bit heavy for the novice, but deals with the calculations required for the bracing calculations required for the design of a deck. Basically Anchor piles or braced piles are required to maintain bracing in both directions. Also bracing calculation involve both wind and earthquake considerations, but in the case of a deck the earthquake bracing demands are always higher than wind bracing demands so the wind bracing requirends are not considered. Anchor piles would be used for lower decks and braced piles for higher decks. The miniumun requirents are set out in this section using BU's (bracing units), and this section also details how the minimum requirements can be achieved using either anchor or braced piles. The calculations also require factors for the earthquake zone and the soil class. To simplify the understanding of this please see the webpage on bracing design with a calculator to help explain the process.
6 Foundation and subfloor framing
This section contains a huge amount of information on the requirements for the posts and the bearers, including how the above mentioned bracing can be achieved. There are also plenty of tables and diagrams to support this section.
7 Floors
Again a huge amount of information on the flooring for decks including joists, joist spacings and nailing schedules. There are also deck specific building codes and diagrams on how handrails need to be fixed to a deck.
9 Posts
This section is not relevant as this refers to posts supporting roofs. For information on posts supporting decks, this under section 6 - foundation and sub floor framing.
To download a copy of NZS 360 Please click here
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