Terrazzo is made by pouring a mix of marble, quartz, granite, or glass chips in an epoxy or cement binder over a prepared concrete slab, then grinding and polishing it smooth. Unlike tile, it is installed in place as a seamless surface. The main stages are slab preparation, crack treatment, divider placement, pouring, grinding, grouting, and sealing.
Terrazzo is not laid down in pieces like tile. It is poured in place and finished on site, which is what gives it a seamless surface with no grout lines to trap dirt or wear out. Understanding how it goes in helps architects, general contractors, and owners plan the schedule and coordinate the work around it. Here is how a commercial terrazzo floor comes together, stage by stage.
What is terrazzo made of?
Terrazzo is a composite. Decorative chips, usually marble, quartz, granite, or recycled glass, are mixed into a binder and then ground and polished to reveal the chips in a smooth, uniform surface. The binder is either epoxy resin or cement, and that single choice shapes much of the installation. Epoxy is a thin-set system used for most interior commercial floors; cement-based systems are used for exterior work and specific structural conditions. You can read more in our guide to epoxy versus cementitious terrazzo.
The terrazzo installation process, step by step
A commercial installation follows a clear sequence. Each stage sets up the next, and rushing any of them shows up in the finished floor.
1. Slab preparation and shot blasting
Everything starts with the concrete slab. The surface has to be clean, sound, and properly profiled so the terrazzo bonds. Contractors typically shot blast the slab, a process that strips away curing compounds and surface contaminants and leaves a clean profile for the terrazzo to grip. A slab that is out of tolerance can be brought into tolerance before the terrazzo goes down.
2. Crack inspection and membrane
Before pouring, the slab is inspected for cracks. Where cracks are present, an anti-fracture or crack-suppression membrane is placed over them. This keeps cracks in the concrete below from mirroring up through the finished terrazzo, one of the most important steps for a floor that stays intact for decades.
3. Divider strip placement
Divider strips are set into the floor. They do two jobs. Structurally, they sit over the slab’s control joints so the terrazzo can move with the concrete without cracking. Decoratively, they define color fields, borders, patterns, and logos. Their placement is planned carefully, ideally coordinated with the concrete pour and saw-cut joints before the terrazzo stage.
4. Mixing and pouring
The chips and binder are mixed to a consistent blend and poured across the prepared surface to the specified thickness. Epoxy terrazzo is placed as a thin topping, as little as 3/8 of an inch. The crew works the material out evenly between the divider strips, filling each field.
5. Grinding
Once the material has cured, the floor is ground with progressively finer abrasives. Grinding is what exposes the decorative chips and brings the surface flat and smooth. This is the stage where the poured material becomes recognizable as terrazzo.
6. Grouting
Grinding can open small pinholes in the surface. A matching grout is applied to fill them, then cured, so the finished floor is dense and continuous with no voids.
7. Final polishing and sealing
The floor gets a final polish to the specified finish, then a sealer appropriate to the system. The sealer choice also influences slip resistance. The result is a hard, seamless, low-maintenance surface ready for traffic.
How long does terrazzo installation take?
Terrazzo installation timelines depend on the size and complexity of the floor, the system used, and how the work is sequenced with other trades. Because terrazzo is poured, ground, and sealed in stages with cure time between some steps, it is scheduled as a coordinated part of the construction timeline rather than a single quick install. Epoxy systems generally have a faster pour-to-grind sequence than cement-based systems. Planning the terrazzo scope early, alongside the concrete and other finishes, keeps the whole schedule moving smoothly.
Why proper installation matters
Terrazzo is one of the longest-lasting floors available, but its lifespan is earned during installation. Slab preparation, crack treatment, divider placement, and careful grinding and sealing determine whether a floor lasts for decades or develops problems early. A properly installed terrazzo floor can be repaired and re-polished many years later and brought back to its original appearance, which is why terrazzo installed generations ago is still in service in buildings around the country.
For a fuller technical picture of terrazzo systems and methods, the National Terrazzo and Mosaic Association is the industry’s authority.
Terrazzo installation by David Allen Company
David Allen Company installs terrazzo as a turnkey operation, from slab preparation through final sealing. Our terrazzo teams have earned more National Terrazzo and Mosaic Association Honor Awards for quality workmanship than all other terrazzo contractors in the Southeast combined, and our terrazzo department has installed more than 50 million square feet of terrazzo across commercial, institutional, and government projects.
You can watch our crews install an epoxy terrazzo floor at NC State’s College of Design in our terrazzo project gallery, or request an estimate for an upcoming project.
Frequently asked questions
Is terrazzo poured in place or made in pieces? Most commercial terrazzo is poured in place, then ground and polished to a seamless finish. Terrazzo can also be precast into sections at a shop and installed on site when a project calls for it.
How thick is a terrazzo floor? Epoxy terrazzo is a thin-set system placed as little as 3/8 of an inch thick. Cement-based systems are thicker and vary by the specific system used.
What is the concrete slab prepared with before terrazzo? The slab is typically shot blasted to remove curing compounds and contaminants and to create a clean surface profile the terrazzo can bond to. Cracks are treated with a crack-suppression membrane before pouring.
Why does terrazzo have metal strips in it? Divider strips control where the floor can move, sitting over the slab’s joints to prevent cracking, and they also define colors, borders, patterns, and custom designs.
Can old terrazzo be restored? Yes. Terrazzo can be ground and re-polished decades later to return it to its original appearance, and minor damage can be repaired. This is one reason terrazzo is valued for its long service life.