Timber flooring can be used over a hydronic underfloor heating/cooling system provided you use hardwood and preferably an engineered hardwood with correct moisture content. AS 2796 states this range to be between 9% and 14%, but research indicates that for Australia’s southern states it is more like 8% to 9%. As there are many different types of timber flooring products on the market, you should check with your flooring supplier if there are any specific issues or considerations before applying underfloor heating and cooling to your timber flooring. Engineered hardwood is structurally stronger and better able to handle the changes in temperature so should be considered as a timber floor covering with hydronic underfloor heating.
Your hydronic system will heat your timber flooring to around 26°C degrees C in winter and cool it to around 18°C in summer. This is a moderate temperature range that will produce the desired comfort levels and not overly stress your flooring.
We recommend that you let your timber flooring acclimatise to the humidity of your home for two days before turning the system on. Then start your hydronic system at 25°C and move the flow water temperature by 2°C per day to reach the desired water flow temperature.
Timber flooring will expand and contract as the relative humidity and floor temperature changes with the seasons.
Therefore, narrow boards will provide more scope for expansion and contraction. Your board thickness should not be less than 19 mm to prevent potential cupping around the edges of the boards. Boards that are too thick will reduce heat transfer. Therefore, Siddons Solar Hydronics recommends engineered hard wood floor boards between 19mm and 25mm in thickness, providing good structural stability and also good heat transfer.