Revisions log for Answer #525
This is the answer to the question What kind of impact sound insulation for underfloor heating?
Revision 1
For hardwood flooring, I recommend full-surface bonding. Better heat transfer = less heating costs, less stress/seam formation, quieter walking noise (in the room itself), easier to sand,....
As a rule of thumb, laminate cannot be glued because a) manufacturers usually don't allow it and b) economically (price of glue : price of laminate) it would be a bit of a disaster.
For laminate (or parquet, if you prefer), look for a substrate with a very low thermal resistance (not to be confused with the thermal conductivity coefficient).
Here we recommend 0.01 m2K/W or less (the upper values are about 0.004 m2K/W). For comparison, 2 mm thick cork has a coefficient of 0.040, as does standard foam foil. So 4 to 10 times more...
The thickness of the substrate is ideal – from 1.5 to 3 mm.