This thread may sound bizzare but I have heard third hand from an electrician that polystyrene used as flooring (commonly known as a floating floor) in modern houses, can wreck cables if they are in contact. Apparently, a chemical reaction occurs between the plastic casing & the polystyrene which eats into the cable, although only power cables were mentioned. The reason I have posted this thread is that I wanted to know from any budding electricians whether this was a 'wind up' or if there is any truth in this. I have recently completed an extension but as an afterthought I ran several coaxial cables under the floorboards between the polystyrene. Okay if true it will take many years but simple measures such as taping the cables would solve this.