Australian Standard AS3700 promotes the use of “bar chairs” or “locating devices” for masonry structures by direct reference to AS3600 Clause 17.2.5 that states:

“All reinforcement, including secondary reinforcement provided for the purpose of maintaining main reinforcement and tendons in position, shall be supported and maintained in position within the tolerances given in Clause 17.5.3 until the concrete has hardened. Bar chairs and locating devices, spacers and tie wires used for this purpose shall be made of concrete, steel or plastics, as appropriate.”

BlockAid Locating Devices, will ensure masonry wall reinforcement achieves compliance.

BlockAid has submitted a Proposal for Change to have “locating devices” added to AS3700-2018 Section 8.5.1 (a) and a Proposal for Change to NCC-2022 to include “locating devices” as a Performance Requirement for reinforced masonry in place of 6mm round bar cross ties.

3 Causes of Non-Compliance

AS3700-2018: 5.9.2
Failure to support the horizontal reinforcement clear of the web when using flush-ended hollow blocks.

AS3700-2018: 5.3 Table 5.1
Failure to provide minimum cover to reinforcement to meet Durability Requirements.*

AS3700-2018: 12.5.3
Failure to maintain lateral tolerance of ±5mm on the placement of reinforcement.

* The Marine Environment (ISO Category 3) extends inland along the Queensland and NSW coast beyond the general distance of 10 kilometres from the surf coast to about 50 kilometres in exceptional circumstances, which includes the Gold Coast, Newcastle, Sydney and Wollongong, thereby increasing the minimum cover to 15mm in these extended areas.

Benefits to Stakeholders

  • Engineer
    Reinforcement placement will meet engineering specification.

  • Certifier
    No risk inspection with BlockAid clearly visible securing the reinforcement.

  • Local Government
    Eliminates non-compliant practices on all projects in their LGA.

  • Construction Company
    Ensures masonry contractors achieve compliance.

  • Masonry Contractor
    Eliminates risk of non-compliance, saves time and material.

  • Building Owner
    Assurance that asset achieves compliance and is insurable.


BlockAid locating devices accurately locate the horizontal reinforcement as the blocks are laid and provide an aperture for the vertical reinforcement to be inserted into the wall, resulting in an accurate lattice of reinforcement throughout the entire wall, to achieve compliance to AS3700.

Australian Governments, Engineers and Certifiers have a vested interest to specify the mandatory use of “bar chairs or locating devices for blockwork” to improve work practice and achieve compliance for block walls, thereby ensuring block wall assets are insurable.


  1. Correctly locate horizontal and vertical reinforcement.
  2. Support the horizontal reinforcement off the web as per AS3700-2011.
  3. Accurately align control joint dowels to ensure the joint functions.
  4. Align the vertical reinforcement to the starter bars.
  5. Ensure adequate grout cover as specified in AS3700-2011.
  6. Core fill without risk of misalignment using current core filling practices.
  7. Facilitate risk-free inspection for Certifiers with clearly visible BlockAids in place.
  8. Eliminate the requirement of steel fixers on critical projects.
  9. Eliminate tying steel in place before core filling.
  10. Save construction time.
  11. Save material by eliminating lapped joints in vertical reinforcement.
  12. Eliminate the risk of insurance claims being denied for damage caused by non-compliance