We have a pump on the floor of the airing cupboard which feeds 2 showers but never at the same time (if that is relevant) and which is very,very, noisy. There is a bedroom either side of the cupboard separated in each case by a plasterboard cavity wall. It is impossible to sleep in either room if one of the showers is up and running. Three of the four pipes attached to the pump are clipped to the wall separating the airing cupboard from one of the bedrooms.
If I filled both cavities with, for example, something like vermiculite, would this go any way towards cutting down the noise? Or is there a better way?
If I filled both cavities with, for example, something like vermiculite, would this go any way towards cutting down the noise? Or is there a better way?

