4-6mm Exposed Aggregate Surface

Updated: 2026-07-21

Overview

Exposed aggregate surfaces with 4-6mm particle size are a specialized concrete finish achieved by removing the top mortar layer to reveal embedded aggregates. This method enhances both functionality and aesthetics, offering a textured, slip-resistant surface ideal for high-traffic outdoor areas. The 4-6mm range provides a mid-size texture that balances grip and visual subtlety, making it versatile for residential and commercial projects. Common aggregates include quartz, granite, and colored pebbles, selected for durability and visual contrast. The technique is popular in landscaping and architectural design due to its customizable patterns and low maintenance requirements. It is often specified for pathways, driveways, and public spaces where safety and design intersect.

Structure and Working Principle

The surface is created by pouring a concrete mix with uniformly distributed aggregates, followed by controlled washing or scrubbing to expose the particles. The 4-6mm size ensures adequate embedment depth while allowing consistent exposure. A surface retarder may be applied to delay the curing of the top layer, facilitating easier removal. The aggregates' hardness (Mohs scale 6+) ensures longevity, while the textured surface disperses water, reducing slip hazards. The finish relies on proper mix design and timing during the exposure process to avoid dislodging particles or over-exposing the substrate.

Key Features

Durability is a hallmark of exposed aggregate surfaces, with resistance to freeze-thaw cycles and UV degradation. The 4-6mm particle size offers optimal traction without compromising comfort underfoot, making it suitable for barefoot areas like pool decks. Customization options include aggregate color blends and patterns, allowing alignment with architectural themes. The surface is also low-maintenance, requiring only occasional rinsing to retain its appearance. Its permeability can be enhanced for eco-friendly designs, supporting stormwater management.

Application Areas

This finish is widely used in residential driveways, public plazas, and commercial walkways due to its blend of safety and aesthetics. In urban landscaping, it complements natural stone or wood elements while providing ADA-compliant slip resistance. For industrial settings, heavier aggregates (e.g., basalt) may be specified for load-bearing surfaces like warehouse aprons. The 4-6mm size is also favored for decorative stair treads and retaining wall caps, where precise texture control is critical.

Maintenance and Precautions

Proper curing (7–14 days) is essential to prevent surface scaling. Avoid de-icing salts, which can spall the aggregate. For cleaning, use pH-neutral detergents and soft brushes to preserve the exposed particles. During installation, temperature control is critical—extreme heat accelerates curing, while cold weather may delay it. Sealants (e.g., acrylic or silane-based) can enhance stain resistance but should be tested for color compatibility. Regular inspections for cracks or loose aggregates help maintain longevity.

B2B Procurement Guide

When sourcing, verify aggregate sourcing consistency to avoid batch variations in color or size. Request samples with the exact 4-6mm grading for approval. Suppliers should provide mix design certifications and ASTM C33 compliance for aggregates. Lead times may vary based on aggregate availability; plan for 2–4 weeks for custom blends. Bulk orders (500+ sq. ft.) often qualify for 10–15% discounts. For international procurement, confirm shipping classifications (aggregates are typically non-hazardous) and moisture-resistant packaging.