Screeds (Concrete) Building Codes & Rules

All Building Classes

NCC 2022 D1P2

May 2023

• Slip resistance performance requirements according to NCC^{NCC 2022 Vol 1, D1P2NCC 2022 Vol 1, D3D15HB 198:2014, 4.3.2 (Table 3A)HB 198:2014, 5.2 (Table 3B)}

Preparing Screeds^{Manufacturer's Requirement}

• Mix
• 1:3 to 1:5 cement to sand (as per Manufacturer's requirements)
• Batch ingredients accurately (i.e. use bucket NOT shovel)
• Add water strictly as directed

Primer / Bonding Agent

15 to 40mm thk Screed^{AS 3958.1:2007, A.2.3 (a)}

Floor Finish

Bonded Screed^{AS 3958.1:2007, A.2.3 (a)}

• ≥ 15mm thk at every point in isolation
• > 40mm thk increased risk in loss of adhesion
• > 50 mm thk reinforcement or scratch coat recommended
• Laid onto bonding agent / slurry to maximize potential bond^Informative
• Used when the screed needs to be at its thinnest
• Ideal for carparks, driveways & other heavy loading applications

Substrate (Concrete Slab)

Adhesive

Benefits^Informative

• Simple to apply because it is thinner than any form of screed
• Reduced shrinkage due to primer use & bonding agent

Substrate Preparation^Informative

• Well compacted
• Repair any defect
• Smooth, clean, dry, & dust / oil free surface
• No sharp edges, back of the shovel finish, nor un-vibrated areas

Floor Screeds

• Compacted to required Levels, Falls & Thicknesses^Informative
• Cure screed according to Manufacturer's requirements^Informative
• Movement joints^{AS 3958.1:2007, 5.4.5.2AS 4654.2:2012, 2.15.2}
• ± 10mm wide
• ≤ 4.5m CTS
• Align with control joints
• Above load-bearing beams or walls

Screed Risks & Failures

• Efflorescence
• Debonding
• Curling
• Cracking

Screed RISKS & FAILURES

NCC 2022 V2