Floor heating can cause issues for wood floors such as warping and gaps between boards due to uneven heating from hot and cold spots. Proper insulation is needed under wood floors for floor heating systems to prevent thermal resistance from being too high and causing temperature differences that damage the flooring. A butter test can demonstrate the effects of hot and cold spots on wood.

1. radiator heating floor heating
hotspot (radiators and ceiling) no hotspots (max temp 27-30°C)
coldspots uncomfortable friendly coldspot
THE PROBLEM WITH FLOORHEATING AND
WOODFLOORS

3. thermo resistance > 0,15 m2K/W

4. Floor heating switched ON :
GAPS

8. floor heating switched OFF
WARPING

20. RESISTANCE 0.0997 m²K/W 0.0997 m²K/W 0.0493 m²K/W 0.043 m²K/W
CONDUCTANCE 0.1 W/m/K 0.1 W/m/K 0.203 W/m/K 0.203 W/m/K

21. 0.053 m²K/W + 0.043 m²K/W = 0.096 m²K/W

22. 0.009 m²K/W + 0.099 m²K/W = 0.108 m²K/W

24. 2mm floam/foil + 15 solid egineered floor
0.06 m²K/W + 0.148 m²K/W = 0.21 m²K/W
resistant to floor heating but not suitable

25. DO THE BUTTER TEST
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