Following on from my earlier question today about making holes in walls, and wondering if it was worth hiring the necessary equipment for £30, SWMBO and I were wondering how to install ventilation for the rest of the bathroom (my question this morning was to do with fitting a light/ventilator over the shower) and SWMBO came up with the idea of fitting another ventilation fan fitting elsewhere in the bathroom, but joining the outlet hose from that to the outlet hose from the shower fan, so we end up having to only make the one hole to the outside.
Is this a bloody good idea, or are there hidden snags that we neither of us have thought about? Would we need some sort of valve arrangement to prevent back flow, and do such valves exist?
TIA
Keith