A wordy thread title there!   There's been some discussion on another thread reference the possible detrimental effects of "cables" being in direct contact with:   - Solid insulation products namely EPS. PU and PIR - Expanding foams (assuming PU) - Silicones / mastics   I'm really no expert on the science of this but have personally seen T&E (twin and earth) "sunk" into EPS walls and similarly into loose fill and solid EPS between joists. It was pointe