Articulation joints - NCC Volume Two, 2019

Background on articulation joints

The provisions for articulation joints were last contained in NCC 2011 but were removed along with the Acceptable Construction Practice (ACP) for masonry in 2012 in favour of the newly developed NCC referenced Australian Standard AS 4773 Masonry in small buildings.

AS 4773 and also AS 3700 Masonry structures both contain provisions for articulation joints, which differ from the previous ACP.

After much consultation between HIA and the Australian Building Codes Board (ABCB) who develop the NCC, it was agreed to reinstate the ACP for masonry veneer in 2019, including articulation joints.

Difference between the Standards and the NCC

The spacing of articulation joints under AS 4773 and AS 3700 is based on soil classification, height of wall, width of joint and whether the wall is painted or rendered for internal and external situations. The provisions can be applied to sites with Class M or H soil classification.

The new ACP can only be applied up to Class M soils and the spacing of joints is based on whether the wall has openings or not. Other factors determine if articulation joints need to be installed, including changes to heights and thickness of walls, at slab construction joints and at wall junctions where different masonry materials are used. These requirements are common to both the standards and the ACP.

Articulation joints and window openings

Under the previous ACP it was not required to continue an articulation joint between a window and a masonry wall where the joint was placed beside a window opening. This was previously achieved by HIA by proposing a change to the provisions to only require articulation joints ‘between masonry elements’, which was accepted by the ABCB.

This wording ‘between masonry elements’ has been retained under the new ACP and now if using the ACP over the Australian Standards when placing articulation joints beside windows, which is common practice, the masonry can finish against the window as long as the required joint is provided above and below the window.

As noted this can only be applied to Class M soils as the ACP is restricted to Class A, S or M soil classifications. Class A or S soils do not require articulation joints.

The diagram shown here is from NCC Volume Two 2019 and is an example of the placement of vertical articulation joints.

To find out more, contact HIA’s Building Services team.

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