Soundproofing a new ceiling

[Martin Pentreath]

I've just taken down a dilapidated saggy lath and plaster ceiling in the sitting room of my victorian terrace. For all its faults it was pretty good at soundproofing between the sitting room and the bedroom above it. I'm getting worried that putting up a single layer of plasterboard and skimming it will give virually no soundproofing.

So, I've been looking at this:

you can see it's basically a system in which the plasterboard is screwed not directly to the joists but to "resilient bars" which insulate it from the existing structure. There would also be some acoustic quilt and acoustic membrane thrown in for good measure, plus two layers of plasterboard.

But now I'm thinking that maybe I'm getting this out of proportion. Does this look over the top for soundproofing within a house? Any simpler ideas?

[Chris Bacon]

Well, use two or three layers then! Don't forget to rake out at the top of the wall to allow the PB to push into a "slot" all around the room:

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[Pufter]

Two layers of plasterboard is good especially if you liberally past the first layer with PVA to bond the second to it - it effectivel becomes one giant thick sheet of plasterboard which is mor noise/vibration resistant due to its mass. Other than that, I thin you'd be better off looking at thicker carpets/underlay upstairs o maybe take up floorboards & fill the void with loose insulatio material. Isolating the ceiling from the joists as you suggest might a best only reduce impact noise (eg. footsteps) rather than airborne nois (eg. TV) so I would say would not be worth the effort

-- Pufter

[bigcat]

2 rather obvious simpler ideas:

1. Push the L&P back up using a wood prop + wood sheet, pour diluted pva glue on top to stick it back to joists, and when done skim the ceiling. This should last very well.
2. Fit laths, and plaster with lime. You can do all that yourself with no skill if you let the plasterer do the final skimcoat. Much faster and easier than wood laths are reed matting, metal EML, or wired bamboo fencing.

People dont seem to think before they take these things down.

NT

[Chris Bacon]

Erm, difficult.

[Rob Morley]

If the old ceiling was adequate then this should give good results without expensive materials or complicated contruction: two layers of 12mm plasterboard overlapping so the joints don't coincide, an inch or two of dry sand on top of that, then fill to floor level with rockwool. Stuff any gaps with rockwool or fill with flexible mastic.

[Tim Mitchell]

In article , Rob Morley writes

Even just 2 layers of overlapped 12mm pb should be pretty effective.

[bigcat]

standard practice for repairing failing L&P

NT

[Steve Walker]

I think he means that it's in rubble bags out the back now.....

[Chris Bacon]

Erm, read Mr. Pentreath's first sentence....

[nightjar]

It depends how noisy you plan to be. I would have thought that a single layer of 12mm plasterboard would be adequate for most houses. However, you can always add a second layer of 12mm plasterboard (with staggered joints) if you find you need to increase the soundproofing once that is up.

Colin Bignell

[Martin Pentreath]

It's true, I didn't think first, and the ceiling is now in the skip! Even with hindsight, I think that trying to save it may have been complicated - it was cracked and uneven and covered in nasty woodchip-type paper and I've had my fill of trying to get that stuff off the hallway and stairs. It also had some not-very-special old cornicing which was falling off in places and would have been hard to repair and may have looked odd anyway with a skim coat on the rest of the ceiling.

Anyway, no use crying over skipped ceilings. I think I may just go for two layers of plasterboard with some acoustic mineral wool to be on the safe side.

[Richard Faulkner]

In message , Martin Pentreath writes

I find that a wooden frame to fit the 2 layers of plasterboard creates a space which dissipates the sound - a bit like double glazing where the bigger the gap between the glass, the better the soundproofing. Then, upstairs, a layer of hardboard, Cloud 9 Cumulus underlay, and carpet, makes for pretty good proofing.

[Richard Faulkner]

In message , Richard Faulkner writes

Or you could fit something like Reduc Strata on the floor above, before fitting the carpet. Add this to the plasterboard, and you would be well in excess of building regs requirements, (not that you have to comply with them).

[mark d]

LOL Floating a ceiling to be flat is about a skillfull and dificult job as you get! Datums, screeds, manipulating a straight edge above your head whilst perched ontop of some kind of scaffolding.

[bigcat]

ah got ya :) General vs specific.

NT