Brickwork Articulation

Articulated walls Brick construction is very brittle and susceptible to cracking due to movement. Movement occurs for many different reasons, including variations in climate or temperature, movement in the frame and movement in the foundations. Articulation joints accommodate these movements in a building. Vertical articulation must be installed in all un- reinforced masonry walls unless the soil has been classed as A or S. Articulation joints are tied at specific intervals and sealed with filler. In straight walls that do not have openings, the articulation joints must be at no more than six metre centres. They must not be closer than the height of the wall away from the corners.

Why do I need joints Footings can be designed to either resist or accommodate movements in the foundation soil. When buildings are constructed on soils that swell and shrink the most sensible approach is to design the footing and structure to accommodate the anticipated foundation movement. Temperature and humidity also cause the brickwork to expand and contract The reason for vertical articulation is to minimise cracking of masonry units and to minimise window and door jamming.

Location of joints From AS4773.1 Masonry in small buildings code Normal width of joint is 10mm for single storey. 15mm for walls greater than 8.5m Most articulation joints can be combined with window openings. The continuous vertical articulation joint, running from the footing to the roof, can be provided on the line of the window jamb. Joint’s do not need to run through the DPC (Damp Proof Course) provided there is not more than 600mm of masonry below.

examples Consider talking about: Cavity walls and ties

How often do I need joints For walls in straight continuous masonry with no openings or changes, see table. If the walls have openings larger than 900x900 then no more than 5m spacing If the opening is >1800 consider putting a joint at both side of the window Note for class E sites, structural design of footings is required.

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Keeping structural stability of the wall Keep in mind that at articulation joints, especially in regard to single skin or full masonry construction (i.e. not brick veneer). Stability needs to be maintained around the joint. This is done by using masonry expansion ties (MET).

Other things to consider Joints must be consistent through finishes, e.g. render. Render also need to be jointed over the DPC To limit cracking from footing movement, suitable precautions include: Adequate drainage for the removal of water from the foundations Ensuring that large trees are not placed adjacent to the footings Correctly sized footings Inclusion of reinforcement in the wall.

More info CMAA guide to Articulated walling (http://59.167.233.142/publications/pdf/TN61ArticulatedWalling.pdf) CMAA guide on unreinforced and reinforced walls (https://www.nationalmasonry.com.au/wp-content/uploads/CMAA-Movement.pdf) Master builders fact sheet on articulated walls (http://keystonetraining.com.au/wp- content/uploads/2011/06/tech-01-articulated-walling-fact-sheet.pdf) AS2870, AS3700, AS4773