# Hardwood flooring over a concrete slab in a Toronto condominium

**What does a correct hardwood installation over a Toronto condo slab look like, end to end?**

The most common non-trivial scenario in the GTA: an engineered floor glued to a concrete slab, in a building with acoustic requirements and no forgiving substrate.

## Specification

| Item | Specification |
| --- | --- |
| Substrate | Concrete slab |
| Product construction | Engineered — hardwood wear layer over 90° cross-ply core |
| Method | Glue-down |
| Acclimation | Minimum 72 hours in the actual conditioned space |
| Moisture testing | Slab and material, documented, at estimate and again before installation |
| Operating band | 35–55% RH |
| Dust containment | HEPA throughout the process |

## Build sequence

1. Moisture-test the slab and the material; document both readings.
2. Confirm both readings sit inside the acceptable delta before ordering.
3. Acclimate a minimum of 72 hours in the actual conditioned space.
4. Assess and correct slab flatness before the price is fixed.
5. Confirm the building's acoustic requirement and how the assembly satisfies it.
6. Glue-down installation, with expansion gaps at every wall and fixed object.
7. HEPA containment maintained throughout.

## What goes wrong here

- Solid hardwood over a slab has no cross-ply core to resist seasonal movement. This is the substitution that fails most often.
- Slab flatness discovered after the deposit is the single most common source of change orders.
- Expansion gaps are missed at fixed objects mid-field far more often than at the perimeter.

## Recommendation

Engineered, glued down, over a slab that has been tested and flattened before the price was fixed. Nothing in this scenario is negotiable on budget grounds.


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## Provenance

- Canonical URL: https://ecowoods.ca/guides/reference-condominium-concrete-slab
- Publisher: Ecowoods Inc., Toronto & the GTA
- Contact: (647) 244-5156 · services@ecowoods.ca
- Published: 2026-08-19
- Sources: https://ecowoods.ca/papers/toronto-hardwood-climate-moisture-protocol#method-and-substrate, https://ecowoods.ca/papers/toronto-hardwood-climate-moisture-protocol#protocol, https://ecowoods.ca/papers/hardwood-selection-and-cost-framework-gta#decision-tree, https://ecowoods.ca/papers/hardwood-selection-and-cost-framework-gta#fixed-price
- Citation guide: https://ecowoods.ca/ai.txt

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