Passivplotter

Hello Pocster, For any "damp" room such as a bathroom or utility room etc. I would always plan on using a foil backed board for the ceiling. I havent come across any acoustic board that has a foil backing so can only suggest a couple of "work-arounds (none of which are perfect). 1. Install a 500 guage vapour control layer (with all joints and edges taped) above a standard 15mm acoustic board, but this will still run the small risk of moisture getting on the back / top side of the board. 2. Use an acoustic board such as the Gyproc Soundbloc MR that has moisture resistant additives added to its core as part of its manufacture. This will have an improved moisture resistance over a standard board, as well as the acoustic benefits. This type of board is intended for moisture rather than movement of vapour, but will have improved performance over a standard board. Without wishing to to tell you how to such eggs, bear in mind that any recessed lights or unsealed penetrations for extract fans etc. in the ceiling will render a foil backing or other solution pretty useless. Also, dont think that accoustic insulation and sound insulation are one and the same. Typically, in a ceiling both would be a rock or mineral wool roll or batt, but different products can and do do different jobs. So dont write off the option of using an acoustic insulant in the ceiling void, particularly if there are going to be penetrations for lights etc. Doubleboarding could be an option, but do consider the additional weight. If you do opt for this option, then stagger all joints and ensure the boards are very tightly butted together to get the best performance. Kind Regards, Matt.