Epoxy terrazzo (thin-set terrazzo) is a high-performance, $3/8”$-thick decorative matrix composed of 100% solids epoxy resin mixed with marble, granite, quartz, or glass aggregates. Unlike traditional cementitious terrazzo systems, epoxy terrazzo offers rapid cure times, high chemical resistance, and vibrant pigment availability. However, because thin-set epoxy lacks the bulk thickness to hide substrate defects, precise surface preparation and subfloor engineering are paramount.
Below is a step-by-step professional installation guide detailing the mechanical, chemical, and field protocols required for a warrantable epoxy terrazzo system.
1. System Architecture & Component Build
An epoxy terrazzo system functions as a continuous, bonded composite:
+-----------------------------------------------------------------------+
| Top Layer: Penetrating Sealer / Finish Polish |
+-----------------------------------------------------------------------+
| Terrazzo Layer: 100% Solids Epoxy + Aggregate Matrix (3/8" Thick) |
+-----------------------------------------------------------------------+
| Divider Strips: L-Angle Zinc/Brass/Plastic Anchored to Flexible Strip|
+-----------------------------------------------------------------------+
| Membrane Layer: Flexible Epoxy Crack Isolation & Vapor Barrier (MVB) |
+-----------------------------------------------------------------------+
| Primer Layer: Penetrating 100% Solids Epoxy Primer |
+-----------------------------------------------------------------------+
| Substrate: Mechanically Profiled Concrete (ICRI CSP 3–4) |
+-----------------------------------------------------------------------+
Step 1: Substrate Testing & Surface Engineering
Before introducing any resinous materials, the concrete slab must meet strict structural and environmental metrics:
- Moisture Audits (ASTM F2170 / ASTM F1869): Conduct in-situ relative humidity (RH) testing. Epoxy resins are non-porous and vulnerable to osmotic blistering if internal slab RH exceeds $80\%$. If RH is high, apply a certified two-component moisture vapor barrier (MVB) primer compliant with ASTM F3010.
- Mechanical Surface Profiling: Shot-blast or diamond-grind the substrate during Surface Preparation to achieve an International Concrete Repair Institute benchmark of ICRI CSP 3 to CSP 4. Remove all laitance, curing compounds, sealers, and surface oils.
- Subfloor Flattening: The substrate tolerance must not exceed $1/8”$ variation in $10\text{ feet}$ ($F_L 50$). Correct low spots, birdbaths, and uneven transitions using high-early-strength cementitious underlayments via Floor Leveling & Floor Flattening.
Step 2: Joint Detailing & Crack Isolation Membrane Application
Epoxy terrazzo is rigid once cured. Substrate movement will telegraph directly through the finish unless properly isolated:
- Crack Routing & Routing Detail: Route dynamic cracks, fill with semi-rigid epoxy or polyurethane joint filler, and apply a 100% solids flexible epoxy crack isolation membrane extended 12 inches on both sides of the crack.
- Full-Coverage Flexible Membrane: For slabs with extensive micro-cracking or elevated stress, apply a full-coverage flexible elastomeric epoxy membrane ($40\text{ mils}$ WFT) reinforced with fiberglass mesh across the entire floor plate.
- Control & Expansion Joints: Saw-cut control joints in the concrete must be honored upward through the terrazzo using back-to-back divider strips or elastomeric joint fill.
Step 3: Layout & Anchor Divider Strips
Divider strips serve two critical functions: controlling structural movement and creating decorative color boundaries or custom logos.
- Strip Selection: Specify $3/8”$-deep L-angle strips in zinc, brass, or plastic (white/black).
- Anchoring: Anchor strips to the substrate along layout lines using 100% solids epoxy adhesive. Ensure strips are perfectly level using laser leveling equipment, as they set the final $3/8”$ finished floor height.
Step 4: Batching, Mixing, and Squeegee Placement
Precise volumetric batching is critical to guarantee uniform color, resin cross-linking, and aggregate density.
- Part A & B Blend: Mix Part A (pigmented resin) and Part B (hardener) using a low-speed mechanical mixer with a Jiffy blade for 2 to 3 minutes.
- Aggregate Addition: Transfer the mixed resin into a mechanical mortar mixer and slowly add clean, kiln-dried aggregate (marble, glass, or granite chips) at the manufacturer-specified binder-to-aggregate ratio (typically 1 part resin to 4–5 parts aggregate by weight).
- Placement & Screeding: Pour the mix onto the primed floor, spread uniformly using hand trowels or screed bars set to $3/8”$ height, and tight-trowel to compact aggregate flat to the surface.
- Seed Aggregate Broadcast: Immediately broadcast additional dry aggregate over the wet surface (“seeding”) and lightly roll with a heavy terrazzo roller to ensure $80\%+$ visible surface aggregate density. Allow to cure for 12 to 24 hours.
Step 5: Multi-Stage Diamond Grinding & Grouting
Grinding exposes the cross-section of the embedded aggregate matrix:
+-----------------------------------------------------------------------+
| Pass 1: Rough Grind (24–36 Grit Metal-Bond Diamonds) + Water Flush |
+-----------------------------------------------------------------------+
| Pass 2: Pin-Hole Grouting (Matching Tinted Epoxy Slurry) |
+-----------------------------------------------------------------------+
| Pass 3: Fine Grind & Honing (100–400 Grit Resin Diamonds) |
+-----------------------------------------------------------------------+
| Pass 4: Polishing & Densification (800–3000 Grit Resin Diamonds) |
+-----------------------------------------------------------------------+
- Rough Initial Grind: Mount heavy planetary grinding machinery with coarse 24-to-36-grit metal-bond diamond segments. Grind wet (or dry with HEPA extraction) to strip the top resin film and flat-grind the aggregate level with the divider strips.
- Grouting Pass: Clean the floor thoroughly. Squeegee a 100% solids epoxy grouting compound (pigmented to match the matrix) across the entire surface to fill all micro-pinholes, air voids, and aggregate pits exposed during rough grinding. Allow the grout to cure for 12 to 24 hours.
- Fine Polish & Honing: Grind off the cured grout film using 80-to-120-grit metal-bond diamonds, then progress through 200, 400, 800, and up to 1,500–3,000 grit resin-bond diamond pads via specialized Concrete Polishing techniques until the specified gloss level is achieved.
Step 6: Sealing and Final Protection
- Penetrating Sealer: Apply an acrylic or fluorochemical water-based penetrating sealer (compliant with NTMA / TERRAZZO standards) to protect matrix pores against oil, water, and staining agents without altering slip resistance (SCOF $\ge 0.60$).
- Burnishing: High-speed burnish the sealed surface using a natural hair pad to harden the seal and enhance specular clarity.
Facility System Integration
Completing a commercial facility involves matching each zone with its specialized surface technology:
- Lobbies & Public Spaces: Thin-set decorative Epoxy Terrazzo or architectural Concrete Polishing.
- Parking Decks & Ramps: Multi-layer elastomeric Traffic Toppings paired with durable Parking Lot Line Painting.
- Mechanical & Loading Bays: High-build Epoxy Coatings & Fluid Flooring or moisture vapor barriers via Surface Preparation.
- Kitchens & Thermal Washdown Bays: Thermal-shock-resistant Trowel-Applied Polyurethane Mortar Flooring.
- Commercial Vehicle Bays: Hot-tire-resistant Garage Epoxy Coatings.
Partner with Epoxy Terrazzo & Surface Specialists in Ontario
Installing thin-set epoxy terrazzo requires precision layout, commercial-grade grinding machinery, technical subfloor remediation, and certified trade craftsmanship.
At AK Level & Polish, we deliver expert substrate profiling via Surface Preparation, subfloor leveling via Floor Leveling & Floor Flattening, architectural Concrete Polishing, elastomeric Traffic Toppings, and high-performance fluid flooring across Toronto, the Greater Toronto Area, and Southern Ontario.
Planning an epoxy terrazzo or architectural resinous flooring project for your commercial facility? Contact AK Level & Polish today to schedule an on-site technical consultation and request a detailed proposal.
Contact Information
AK Level & Polish Inc.
📍 895 Don Mills Rd. Suite 900, Toronto, ON M3C 1W3
📞 +1 (647) 768-8517
✉️ aklevelandpolish@gmail.com
