When I have my heating installed in the new house I'm going to insulate all the pipework under the floor and in chases etc. In my current house where the pipes cross joists in notches they have some sort of awful hairy fibrous material around them to prevent that awful expansion clicking I assume. And it works. We never can hear when the heating has come on or off. No clicking at all. What is suitable to use for this purpose today? Or could I just carry on the insulation and squash it into the notches? Doesn't feel right.