Replacing a lathe and plaster ceiling - what level of soundproofing needed?

[betterwhenthesunshines]

Our original thick lathe and plaster ceiling cracked and had to come down in November. No joy on insurance. 4 roofers have now told me I don't need the felt roof over the bay re-doing, just some pointing on the flashings.

Room is 5.5m x 4m with carpet in the room above. But I don't want to hear more than we did previously. We never had any noise issues but obviously just one thin layer of ceiling board is not going to be sufficient. I just don't want to be able to hear conversations, radio, TV etc. I don't mind if I can hear that it's on, but I don't want to know what the song is if that makes sense!

I was thinking 100mm acoustic insulation between joists (AMW60 100mm 60kg/m3 density) and then a single layer acoustic plasterboard (19mm high density) would be enough. If that really isn't enough we could always put rubber acoustic sheeting under the carpet in daughter's room later?

But the soundproof people are recommending resilient bars, with a 19mm + 12.5mm plasterboard sandwich in addition to the joist insulation. It seems these are better at reducing contact noise eg if you have laminate above. But my plasterer / decorator hasn't fitted these before. ARe they worth it? Is it fairly straightforward?

I have another quote from a bigger building firm to do the whole thing, but their costs are excessive: £5k + the cost of replacement cornices, not including decoration...

Pandeen / Piglet John, any advice? Anyone else done this?

[betterwhenthesunshines]

Anyone? Even if you've just replaced with standard plasterboard that would help - do you have any noise issues?

[allthatglittersisnotgold]

Hi,

We replaced an entire lathe and plaster ceiling in our master bedroom, with plaster board, as well as ripping down a few walls to put insulation between the boards, mesh under the window (as wall is warped and moves and cracks!) Then replastered the lot. Cost about 1.6k. Not had any dealings with soundproofing, but neighbours below put some sort of "soundproofing" on top of their ceilings (I assume it helps with them hearing us moving around). Not sure hwo much they paid. I hope that helps a little. We are in London and that quote was at the slightly lower end.

[PigletJohn]

Two layers of dense plasterboard, plus skim, would be about equivalent to your old lime-plaster ceiling, which was probably thick and heavy. Fibrous cornice needs skill and will cost extra, I expect you need fibrous coving as well.

Dense batts between the joists will reduce airbourne noise.

The extra decoupled ceiling would make an improvement, especially if people are dancing about upstairs with no carpet and underfelt. but I don't know how much. It sounds like you have a specialist noise contractor, ask them to provide figures.