A glass balustrade is a barrier first and a view second

Glass on a deck is sold as a view. The National Construction Code sells it as a barrier to prevent falls. If you only remember one sentence from this hub, remember that. Height, openings, climbability and structural actions are not optional extras you add after you pick a clamp.

This page is for Class 1 housing language in the ABCB Housing Provisions. Other building classes live in Volume One. We are not writing a commercial atrium guide, and we are not a balustrade shop.

When 11.3.3 wants a barrier

A continuous barrier must be provided along the side of a trafficable surface such as:

• a stairway, ramp or the like
• a floor, corridor, hallway, balcony, deck, verandah, mezzanine, access bridge or the like
• a roof top space or the like to which general access is provided
• any delineated path of access to a building

where it is possible to fall 1 m or more, measured from the trafficable surface to the surface beneath.

The clause lists exceptions (some retaining walls, openable-window barriers covered by 11.3.7 and 11.3.8, and some AS 1657 industrial access). Do not invent a fourth exception for a “low-use” deck. If the fall is a metre, you are in the clause.

Swimming-pool barriers are a different sentence. The Housing Provisions point pool safety barriers to H7D2. Do not specify a deck balustrade with a pool-fence brochure.

How 11.3.4 wants it built

Height. Not less than 865 mm above stair nosings or a ramp floor. Not less than 1 m above the floor of a landing, corridor, hallway, balcony, deck, verandah, access path, mezzanine, access bridge or roof top space to which general access is provided. A landing barrier along the inside edge, not more than 500 mm long, may be 865 mm. A transition zone may join the 865 mm flight to the 1 m landing.

Openings. Constructed so they do not permit a 125 mm sphere to pass. On stairs, measure above the nosing line. A non-habitable attic stair used irregularly has a narrower exception in 11.3.4(7) — 300 mm sphere or a two-rail geometry. That is not your everyday deck.

Face-fixed gaps. If the barrier is fixed to the vertical face of the landing or deck, the opening between barrier and face must not exceed 40 mm, measured horizontally from the edge of the trafficable surface to the nearest internal face of the barrier.

Climbing. Where a fall of more than 4 m is possible, horizontal elements between 150 mm and 760 mm above the floor must not facilitate climbing. The explanatory note treats window sills and transoms in that band as climbable when the window is part of the barrier.

Glass and load. A glass barrier or window serving as a barrier must comply with H1D8 and the rest of Part 11.3. A barrier, except a window serving as a barrier, must be designed to take loading forces in accordance with AS/NZS 1170.1.

Where AS 1288 sits

Standards Australia describes AS 1288:2021 as the standard for choosing and installing glass in buildings, including special applications such as barriers. NCC Volume One B1D4 lists “glazing used in balustrades and sloping overhead glazing” among the assemblies that must comply with AS 1288. Housing Provisions 8.3.1 requires glass used in barriers, except a window serving as a barrier, to withstand AS 1170.1 loads, and glass of a type within the scope of AS 1288.

We will not recite paywalled clause numbers from AS 1288 as if this site were the standard. Ask the designer for the AS 1288 path they used (structural pane versus infill, handrail type, interlayer) and for the 1170.1 actions. If they cannot name those, you do not yet have a specification.

Windows that are also barriers

A window can form part of a barrier. The Housing Provisions explanatory text says that window is then under Section 8 for the glazing assembly and is not required to comply with AS/NZS 1170.1, because Section 8 already considers wind and human impact. The window still has to meet Part 11.3 for height, openings and climbability. See windows and doors and the longer barrier guide.

What to put on the drawing

Fall height, barrier height, sphere check, face gap, wind region or 1170 actions, glass type, and whether a handrail is load-supporting. Costs will move with span, interlayer, posts, and access. We still will not print a number.

If a salesperson leads with “frameless 12 mm”, lead with 11.3.3. The view can wait until the barrier is a barrier.

Field note on balustrades (1)

Fall height, barrier height, sphere and 1170.1 actions belong on the drawing before the clamp.

Keep Housing Provisions 8.4 open if people can hit the glass. Keep Part 11.3 open if people can fall. Keep B1D4 open if you are arguing about AS 2047 versus AS 1288. Then write the clause on the request for quote and let a licensed practitioner correct you.

This site will not invent a price, a ranking, an operator or a statistic to decorate that loop. If you need a guest-post citation, cite the ABCB or Standards Australia page, not a memory of this paragraph. If you need a pane on Friday, you need a glazier, not another sentence from an editorial desk.

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