Soundproofing and insulation between floors in a conversion

scottishblondie

We live in the ground floor of a 1920s house which was converted to 2 flats in the 70s. We’re planning to have a bedroom and en-suite renovated soon, which in the original conversion were a kitchen and utility area.  The ceilings were lowered significantly, and we want to raise the bedroom one back to close to the original height. 

We had a peek with an inspection camera and after poking through about a metre of fibreglass insulation discovered that the original ceiling is no more - we could see the joists and floorboards of the room above. 

I’m wondering what the best approach to soundproofing and insulating this is. We don’t know how much noise transmission there is just now - this is a spare room and the room above is the neighbour’s spare room - but this is going to be the only time we’ll have this ceiling down so I want to make sure it’s properly done. Can anyone advise what should be fitted?

daivid

Are you on good terms with the neighbours? Could you ask them to go in and jump up and down a bit, stick a radio on etc to get an idea of how much of a sound problem there could be. If there is a potential issue what needs/ can be done depends on the type of transmission. For airborne sound e.g. talking, tv then I've found 50mm acoustic slab by rockwool to be effective - this is in my own house however where everyone tends to be quite reasonable and considerate. For percusive transmission of sound e.g. vibrations from walking traveling through the boards then beams then ceiling the remedies are more complicated often involving isolating (dampening) the ceiling from the floor above so the vibrations cannot travel straight through. Perhaps the large void created was in part to reduce the noise transmission, by raising the ceiling you could be creating a noise problem that didn't exist previously.

scottishblondie

Yes we're on good terms, I'll ask them to do that.  This is to be the nursery for our new arrival next year and I really don't want the baby woken up by clumping feet!  We can hear some things very clearly in other rooms.  The flat was "modernised" in 2014 (weirdly except for the bedroom/bathroom in question) and all the ceilings have been lowered a bit aside from one room which has been left "original" - but I don't know what is above those ceilings.  The previous owner said "a load of insulation", but given the corners we've found cut elsewhere... it could be anything or nothing!