Code compliance of a proposed pergola as a barrier
Figure 1: The window with the propsed pergola as a barrier.
This determination arose from a dispute between the building consent authority (BCA) and a homeowner about whether a pergola would form a Code-compliant barrier to provide safety from falling from a first-floor window to a house. The owner applied for the determination because the BCA refused to accept the proposal complied with Building Code Clause F4 'Safety from Falling'.
The proposed pergola and window are shown in Figure 1 above. The window had a 270 mm wide sill, 430 mm above the floor ('the window upstand') and a maximum opening width of 4.5 metres. The proposed pergola was 6.5 metres long.
Determination 2001/2 considered a horizontal canopy made from tensioned wires that formed a barrier for a roof deck to which access by small children could be controlled. The determination accepted that the deck, in combination with the canopy, complied with Clause F4. Determination 2008/81 considered a landing area 1200 mm wide provided adequate protection in the case of a fall from a deck less than 1 metre in height.
The height of the fall onto the proposed pergola from the window sill was less than 1 metre, and, as for the canopy in Determination 2001/2, the change of level from the pergola to the ground was at the outer edge of the pergola. The pergola was to be located along the full length of the window opening. The pergola was 1300 mm wide, and as in Determination 2008/81, it was accepted that this would provide an adequate landing areain the case of a fall.
The determination considered a living space in a house was an area that children under six were likely to frequent, whether under adult supervision or not.
The Building Code in Clause F4 recognises differences in physical size and behaviour between adults and children under six years of age. Accordingly, the determination considered that the effectiveness of the pergola as a barrier from falling would be different for adults than it would be for children under six years of age, and particularly that children under the age of six may not act as rationally as adults in seeking a position of safety. An adult who fell onto the pergola would be able to return to a position of safety by climbing back over the window sill. Children, particularly those under the age of six, would have to negotiate a height of 630 mm and a sill depth of 270 mm in order to return to a position of safety. Easy access onto the pergola over the low upstand would place a child in a hazardous position.
The window upstand was not considered Code-compliant as it did not restrict the passage of children under six.
In accordance with section 188 of the Building Act 2004, it was determined that the proposed combination of the 430 mm window upstand and the pergola did not provide a design solution that complied with Clause F4 of the Building Code.
Code compliance of timber barriers to a deck, stair and pool
Figure 2: Section and elevation of the balcony barriers.
This determination arose from a dispute between the BCA and a homeowner about whether the timber barriers to a deck, pool, and exterior stairway of a house comply with Building Code Clause F4 'Safety from Falling'. The owner applied for the determination because the BCA refused to issue code compliance certificates for the building consents that included the barriers.
The building work consisted of solid cedar barriers that protected upper-level decks and lower-level terraces ('the balcony barriers'), and the barrier to the stairway ('the stair barrier').
The balcony barriers
The determination compared the balcony barriers to a similar barrier described in Figure 1 in Acceptable Solution F4/AS1. The overall height of the barrier exceeds the 1000 mm dimension shown in Figure 1, and the bottom rail, at 280 mm above the balcony, is also higher than the 150 mm dimension shown in Figure 1. However, the distance between the top of the bottom rail and the top of the next rail above is 575 mm, which is less than the 610 mm dimension shown in Figure 1.
The determination considered the shape and width of the top rail meant that a child would need to reach over the top to obtain a grip, which would not be easy for a small hand. In addition, the thick sections of all the barrier members would not be attractive to children as they were not easy to grasp.
Consequently, the balcony barriers would be as difficult for children under the age of six to climb as the barrier shown in Figure 1 of F4/AS1, and therefore complied with Building Code Clause F4.
The stair barrier
The determination compared the stair barrier to the similar barrier in Acceptable Solution F4/AS1. The determination found that the stair barrier complied with Clause F4, with the exception of the requirements for pool fencing.
The stair barrier as a pool barrier
The lower parts of the stair barrier also formed a part of the perimeter fence to a swimming pool.
Acceptable Solution F4/AS1 says the Schedule to the Fencing of Swimming Pools Act 1987 is a means of establishing compliance with Clause F4 with respect to the fencing of swimming pools.
As the lower stair barrier was less than 1.2 metres above ground level, the barrier did not comply with the requirements of Clause 1 of the Schedule to the Fencing of Swimming Pools Act 1987. In addition the stair barrier did not comply with Clause 5A of the Schedule, which required a clear 900 mm dimension between horizontal supports. In this instance the stair barrier had upper and lower timber blocks located between the barrier uprights, and the dimension between the blocks was significantly less than 900 mm.
If the timber blocks were removed the 900 mm dimension would be achieved, which would satisfy Clause 5A. The 215 mm wide handrail would also give an extended gripping distance, which would offset the barrier height being less than 1.2 metres. The slope of the handrail would also make it difficult to climb. The barrier would there-fore comply with the requirements of the Building Code as an alternative solution.
In accordance with section 188 of the Act, it was determined that:
- the barriers complied with Clause F4 of the Building Code with respect to forming a code-compliant barrier to the balconies and stairs
- the lower part of the stair barrier did not comply with Clause F4 with respect to the requirements for the fencing of swimming pools.
These are summaries only. The full determinations (along with all other determinations issued) can be viewed on our website: www.dbh.govt.nz/determinations