Requirements for barriers and handrails

A trafficable surface is anywhere where a person would normally walk to get from one place to another, being either from the street, throughout the house or from the house to another building. 

This is particularly important when considering if a barrier is required adjacent to a retaining wall. The provisions only apply where the retaining wall is associated with a delineated path of access to a building from a road, or between buildings. 

Figure 1: Barrier for retaining walls 

This is not a new provision. The figure below has been added to clarify that where it is possible to fall 1m or more from a walkway or path leading from the street to the house, garage to a house, etc., that is supported by a retaining wall, a barrier is required to be provided. 

It does not apply to a retaining wall used for landscaping or terracing in the backyard. The clause states that: 

The requirements do not apply to: 

a retaining wall unless the retaining wall forms part of, or is directly associated with, a delineated path of access to a building from the road, or a delineated path of access between buildings (see Figure 3.9.2.2).

Figure 3.4.2.2

The construction of a barrier must comply with the following (these provisions have not changed but they have been renumbered with some editorial improvements): 

• The height must not be less than 865mm above the nosings of the stair treads or the floor of a ramp
• The height must not be less: 
• 1m above the floor of any access path, balcony, landing or the like (see NCC Figure 3.9.2.2 and figure 3.9.2.3), or 
• 865mm above the floor of a landing to a stairway or ramp where the barrier is provided along the inside edge of the landing and does not exceed a length of 500mm 
• To enable a smooth transition from stairway flight to landing a transition zone may be incorporated where the barrier height changes from 865mm on the stairway flight or ramp to 1m at the landing. (see NCC figure 3.9.2.4)
• Openings in barriers (including decorative balustrades) must be constructed so that they do not permit a 125mm sphere to pass through it. For stairs the opening is measured above the nosing line of the stair treads. (see NCC figure 3.9.2.3) 

Figure 3.9.2.3

Figure 3.9.2.4

• Where it is possible to fall more than 4m from the floor of a trafficable surface to the surface beneath, any horizontal elements within the barrier between 150mm and760 mm above the floor must not facilitate climbing. 

All barriers, except a window serving as a barrier, must be designed to take loading forces in accordance with AS/NZS 1170.1.

The provisions for handrails to stairs and ramps are now required to be provided in Class 10a buildings. The exemption in NCC 2016 not to apply to Class 10a has been removed.

Therefore, in a Class 10a building as well as a Class 1 building where a stairway or ramp is providing a change in elevation of 1m or more (i.e. greater than five risers) a handrail will be required. 

As a minimum requirement, handrails to a stairway flight or ramp must be provided on at least one side of the stairway or ramp and for the full length of the stairway flight or ramp. It must be continuous and have no obstructions that will tend to break a handhold except for a newel post or ball type stanchion. 

As with barriers the top surface of the handrail must be at least 865mm vertically above the nosings of the stair tread or floor surface of a ramp. 

For stairways with winders it is important that the handrail continues on the same side from top to bottom to be a continuous handrail. It is not appropriate in stairs with winders to change the handrail to the other side of the stairway at the newel post as it will no longer be continuous from the top to the bottom. See Figure 2. 

Figure 2

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Figure 3

For stairways with landings, a handrail is not required to the landing at the top or bottom of a flight or between two flights (except where a person could fall 1m or more from the landing). See Figure 3. 

The NCC has now changed the layout of the clauses relating to protection of openable windows. There are now two clauses: 

• 3.9.2.6 for an openable window in a bedroom where the floor below the window is 2m or more above the surface beneath 
• 3.9.2.7 for an openable window in a room other than a bedroom where the floor below the window is 4m or more above the surface beneath. 

There are also new diagrams that clarify the clause requirements. See figures 4, 5 and 6. 

3.9.2.6 requires any openable window where the sill is less than 1.7m above the floor must have a device capable of restricting the window opening or a securely fitted screen. If the device or screen can be removed then additional requirements must be provided. 

Figure 4 and 5

Clause 3.9.2.7 requires an openable part of the window if the sill is below 865mm from the floor to be protected with a barrier with a minimum of height of 865mm, have non-climbable elements between 150 mm and 760mm above the floor and not permit a sphere of 125mm pass through the opening. 

Figure 6