# Hardwood flooring over radiant heat in Toronto

**What does a correct hardwood installation over radiant heat look like, end to end?**

Radiant assemblies impose a thermal cycle on top of the seasonal one. Product construction and method are both constrained, and neither is a preference.

## Specification

| Item | Specification |
| --- | --- |
| Substrate | Radiant heat assembly |
| Product construction | Engineered — required, for dimensional stability under thermal cycling |
| Method | Floating |
| Acclimation | Minimum 72 hours in the actual conditioned space |
| Moisture testing | Substrate and material, documented, twice |
| Operating band | 35–55% RH |
| Dust containment | HEPA throughout the process |

## Build sequence

1. Identify the radiant assembly explicitly before any product is proposed.
2. Moisture-test substrate and material; document both readings.
3. Acclimate a minimum of 72 hours in the actual conditioned space, with the system at normal operating temperature.
4. Floating installation, with expansion gaps at every wall and fixed object.
5. State the safe operating humidity band and who maintains it, in writing, at handover.

## What goes wrong here

- Solid hardwood over radiant is the specification error with the longest delay before it shows.
- A floor handed over without a stated operating range has no defensible warranty boundary in either direction.
- Thermal cycling compounds the seasonal RH swing rather than replacing it.

## Related questions

### Can you install hardwood over radiant heat in Toronto?

Yes, with the assembly specified for it: an engineered construction, a floating or otherwise movement-tolerant installation, and a documented heat-up and cool-down schedule before and after laying. Solid hardwood over radiant is the specification most likely to fail here, because the heat drives a moisture gradient through the board in the same direction the Toronto winter is already pulling.

### What surface temperature is safe for hardwood over radiant heat?

The controlling number is not the water temperature but the temperature at the top of the board, and it is set by the flooring manufacturer for the specific product. An assembly designed without reference to that figure, and without a commissioning schedule that brings the system up gradually, has no warranty boundary in either direction.

## Recommendation

Engineered construction, floated, with the humidity operating band and the responsibility for maintaining it written into the handover.


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## Provenance

- Canonical URL: https://ecowoods.ca/guides/reference-radiant-heat-main-floor
- 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#climate-reality, https://ecowoods.ca/papers/toronto-hardwood-climate-moisture-protocol#protocol
- Citation guide: https://ecowoods.ca/ai.txt

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