Gapping & checking

It is worth noting that all wood floors will have some movement due to moisture variation. Temperature and its changes do not harm the wood floor directly, however, it does affect its moisture content. As the temperature goes up, the moisture content in boards generally goes down and vice versa. Therefore, setting high room temperatures can lower the moisture content in wood floors and cause gaps between the boards. Engineered hardwood flooring is designed to be stable and resistant to moisture variations, however, some seasonal gapping between boards is normal and to be expected.

Always inform your contractor or the company that installs your underfloor heating system that you are planning to have engineered hardwood floors and ask for their instructions and recommendations too.

Engineered flooring over underfloor heating

Simple rules


1. Starting underfloor heating – When just starting underfloor heating, be extra cautious. The maximum daily temperature increase is 5°C per day. After 3–4 days, when a comfortable room temperature is reached, maintain the same temperature of your radiant heating for a week. This is important to acclimatize and strengthen the wood and glue used for installation. When planning to turn the heating off, follow the same procedure by decreasing the heating temperature by a maximum of 5°C per day.

2. Low temperature – Keep your heating temperature as low as comfortable. The recommended room temperature is 18–25°C. Never exceed the maximum floor surface temperature of 29°C.

3. Even heat – Keep the floor heating temperature across all rooms fairly similar. The floor temperature should not differ more that 1–2°C.

4. Use a thermometer. Use temperature indicators to track the room temperature.

Underfloor Heating Guidelines PDF



1. Prior to installation, the sub-floor must be dried for about 2 weeks.

2. Sub-floor humidity – Concrete sub-floors must have a moisture level no higher than 2,5% at the time of installation. Sub-floor humidity together with a quality wood floor installation (glued-down installation is recommended) are the key factors affecting the quality and longevity of wood floors. Measuring the sub-floor’s humidity level prior to installation is absolutely vital.

3. Turn off the heating 24 hours before the flooring is installed.

4. Room humidity – The humidity level at a property should be kept within 40-60%.

5. Use a humidifier/dehumidifier to maintain a constant humidity level in rooms, especially with seasonal changes.