I recently put up a cooker hood on an internal wall on the recirculation setting. When I drilled the holes they went through to the cavity, the walls are very hard, drill dust is pale and gritty. I live in a mansion block and when I turn on the cooker hood it reverberates through the building, not good for neighbour relations. Is there any solution to deaden the impact, some rubber between cooker hood and wall or something? There is no cupboard above the hood.