Concrete interior finish costs in a residential project are more variable than most clients expect. The surface you see at the end — smooth, gray, continuous — does not reveal the number of steps required to produce it. Understanding those steps lets you make specification decisions that control cost without sacrificing the quality that makes the material worth using.
The Cost Structure of a Polished Concrete Floor
A polished concrete floor is not a single line item. The cost builds through a sequence:
Slab preparation: if the concrete is existing, it may need crack injection, level grinding of high spots, or adhesive removal before polishing can begin. A new slab poured to specification requires less prep, which is part of why the floor specification belongs in the structural documents.
Grinding sequence: industrial diamond grinders start at coarse grits (typically 16 or 30 metal-bond) and progress through 6 to 8 finer grits before reaching the final polish level. Each pass takes time. A fully polished floor (1,500 to 3,000 grit) requires more passes than a satin finish (400 to 800 grit). More passes means more labor cost.
Densifier application: a liquid lithium or sodium silicate densifier is applied midway through the grinding sequence. It reacts with calcium hydroxide in the concrete to form additional calcium silicate hydrate, hardening the surface and improving polishability. This is a material and application cost but not a labor-intensive step.
Sealer application: penetrating sealer is one to two thin coats. Topical sealer is multiple build coats with drying time between applications. Labor cost difference is significant.
New Slab Versus Existing Slab
A new concrete slab poured to specification for polishing is the cleanest starting point. The aggregate is known, the flatness tolerance is enforced from the start, and there are no previous finishes to remove. The total cost is the pour, the flatness surcharge if required, and the polishing sequence.
An existing slab in a renovation introduces unknowns. We assess the slab before committing to a polished finish specification:
- Age and condition of the concrete (minimum 28-day strength required; old slabs may have carbonated surfaces)
- Previous finishes (tile adhesive, paint, or epoxy coatings require removal and may have altered the surface)
- Flatness (grinding can remove up to 3 to 5mm of high spots; larger deviations require more aggressive correction)
- Cracks (cosmetic cracks can be injected and ground; structural movement cracks will reappear)
When the existing slab passes assessment, polishing is the most economical path to a high-quality floor in a renovation because it uses the material already in place.
Wall Finishes: The Other Concrete Surfaces
The cost structure for concrete wall finishes is different from floors. The two main approaches:
Cast-in-place concrete walls: formed, poured, stripped. The form material (plywood, board, metal) determines the surface texture. Board-formed concrete uses horizontal planks to leave a wood grain impression in the surface. Fair-faced concrete uses smooth plywood for a flat, neutral surface. Cost is driven by formwork labor, which is typically more than the concrete itself.
Applied concrete finishes (microcement, concrete overlays): thin-layer products applied over an existing substrate. They can achieve a concrete appearance on walls, floors, or even curved surfaces where casting would be impractical. They are not structural concrete — they are finish products that mimic the visual quality. Cost is lower than cast-in-place but depends heavily on substrate preparation.
In MÉTODO we use applied concrete finishes primarily in renovation contexts where cast-in-place is not structurally possible. In new construction we specify cast-in-place where the budget allows because the result is more durable and reads as what it is.
Budget Allocation for a Concrete Interior
If concrete finishes are part of a larger residential project, the allocation question is which surfaces justify the higher specification cost.
Floors in primary living areas are the highest-value investment: they cover the most area, receive the most traffic, and are the most visible surface in the space. A carefully specified polished floor in the main living and dining areas sets the tone for the rest of the design.
Concrete walls are a secondary investment. A single feature wall in board-formed concrete in a living room or stair hall can anchor the material palette without committing to concrete on every surface. This is the matrix of options approach: decide where each material performs best and concentrate the budget accordingly.
Ceilings in concrete are a structural condition, not a finish choice. If the structural slab is exposed — a common condition in open-plan residential architecture — the quality of the concrete pour determines the ceiling appearance. Specifying the pour for an exposed ceiling is a cost in the structural budget, not the finish budget.
Próximos pasos
Understanding the real cost of a concrete interior finish requires a project-specific analysis, not a per-square-meter rule of thumb that ignores the condition of the existing slab and the specification level you want. We can help you develop that analysis at the start of the design process so the budget is based on reality.
Conoce el método de MÉTODO to see how we approach cost transparency in residential architecture.