Concrete Mix Requirements

---

A quality concrete mix is only half the battle; the concreter’s placement technique is the critical factor in the final aesthetic.

• Machine Trowelling: The slab must be power-floated and burnished to a dense, hard finish. This "burnishing" closes the surface pores and flattens the "cream," which is essential for minimizing pinholes and achieving high-clarity reflection.
• Vibration & Compaction: Proper mechanical vibration is vital to consolidate the mix and push aggregates down. This is non-negotiable if a "Nil Exposure" (Burnished) look is the goal.
• Curing Time: To reach the full compressive strength required for diamond refinement, the slab must ideally cure for 28 days before the final polishing stages begin.

Surface Regularity & Flatness Standards

We work to Australian NATSPEC Class A tolerances to ensure your floor looks like a single sheet of glass, not a series of waves.

1. The Standard (SR2): For a high-end finish, the slab should meet SR2 (Surface Regularity 2) standards—meaning no more than a 5mm deviation over a 3-metre straight edge.
2. Architectural Grade (SR1): For Minimal (Salt & Pepper) finishes, we require SR1 (3mm deviation). Any "waves" in the slab will cause the grinder to cut too deep into high spots, resulting in patchy, inconsistent stone exposure.
3. Flatness vs. Levelness: A floor can be level (not sloping) but still "un-flat" (wavy). To avoid patchy exposure, builders must use a highway straight-edge and bull float during the pour to eliminate undulations.

Solutions for "Out-of-Spec" Slabs

If a slab is wavy or the F-Numbers (FF/FL) are low, we pivot to ensure you still get a premium result:

• Full Aggregate Exposure: By grinding deeper to "bottom out" the valleys in a wavy slab, we can achieve a consistent, full-stone aesthetic even on uneven floors.
• The HP Guard Pivot: If you require a consistent, minimal-exposure look on a poor-quality slab, our HP Guard system is the solution. As a high-performance topical film, it provides a uniform, mirror-like gloss that masks substrate imperfections that mechanical polishing cannot.

For existing slabs that don't meet the strict density requirements for mechanical polishing, we offer the HP Guard Polished System—a high-performance, topical solution that delivers a premium aesthetic while reinforcing and protecting out-of-spec concrete