Replacing a lath & plaster ceiling

[unseen]

First time post so please be gentle (ooer! ) And please accept my appologies if I'm posting in the wrong place

I've just finished pulling down the last of an old lath and plaster ceiling and I'm after some advice in regards plasterboarding it. It's a downstairs living room with my kids bedroom above.
I know (from searching and reading various posts here for the last few days) soundproofing a ceiling seems to be a bit like voodoo.. I've looked into the various products available and rockwool flexi seems like it could help a little, does anyone know of a supplier in the NW/Manchester area?

Also could I safely double up 12.5mm plasterboard using 75mm screws or is there risk regarding the weight? If it helps the house is an end terrace built early 1900's.

Many thanks in advance.. And again apologies if I've posted this in the wrong forum.

Rob

 

[l200]

Sheffield insulations are nationwide supplier ,would probably have a good technical department ,they supply both insulation and plasterboard so may be able to answer both questions , i know very little about soundproofing but it is probably big business due to planning laws regarding apartments etc , sheffield insulations would be my first call,
if i were to double board ceiling i would fix first layer with 40mmish screws then 2nd with 70mmish screws (belt and braces approach)
hope it's some help

 

[shenks]

Another NW supplier of Rockwool Flexislabs is CW Berry, Leyland, Telephone 01772 431216.

I have used Flexislabs (both 50mm and 70mm) in a recent build and refurb and it does make a difference to the soundproofing - probably not as much as a true acoustic solution but certainly much cheaper. Double boarding also makes a difference to the soundproofing since you need to get a combination of mass (plaster and boards) and dispersion (fibre/wool) for best results.

 

[noseall]

due to the fact you have timber joists and not p.c. concrete beams, means that sound deadening and not 'proofing' is what you will end up with.

filling the void with a fibre type insulation (definitely not rigid type) will help, but doubling up on the plaster board will help considerably. adding weight always helps reduce the travel of sound.

as for the extra weight on the joists, don't sweat it. the joists will hardly notice.

 

[unseen]

as for the extra weight on the joists, don't sweat it. the joists will hardly notice.

Your a bloody mindreader noseall I swear!! Yep.. That was the one thing that kept creeping into my mind was "will it hack the weight"... Thanks for that.. In fact thanks all for the advice I seriously appreciate it!

I've now located somewhere that sells rockwool flexi.. But looking at it.. I think Knaufs Joist insulation 100mmx400mmx1200mm might be a better product? Thinking more as old house=no chance of 400mm centres.. Whats the best thing to hold it up with (apart from my hands before someone starts that one!! ) Chicken wire?

Thanks again guys....

Rob

 

[noseall]

if you have some old bits of wood or even bamboo, so long as it is cut so that it wedges snug between the joists, it will be enough to hold up lightweight insulation.

we even cut strips of plasterboard to hold up the inso!

 

[Thermo]

one other bit of advice, hire a plasterboard lift for the day to do it with. It will cost about £30 and makes life so much easier especially if its you on your own!

 

[joe-90]

Once the sound vibrations are in the fabric of the building - forget about soundproofing - it doesn't work.

Just put a carpet and thick underlay in the kids bedroom.

 

[unseen]

one other bit of advice, hire a plasterboard lift for the day to do it with. It will cost about £30 and makes life so much easier especially if its you on your own!

Heh.. Already sussed that one.. booked it for pickup on friday only snaglet now is to explain to the missus that the plasterboard delivery might arrive while i'm picking up the lift.... Ho hum guess who's dinner will be in the dog on friday!

 

[unseen]

Once the sound vibrations are in the fabric of the building - forget about soundproofing - it doesn't work.

Just put a carpet and thick underlay in the kids bedroom.

Hmm... When the kids bedroom was above the dining room (standard 9.5mm ceiling and laminate with the greenboards under in their room) you could hear the odd noise (mainly when they were dancing.. all girls *sigh*) so I'm working off the theory that going that wee bit further should help improve it more..
If I'm honest tho.. It's more to deaden the sound from the living room don't think they'd sleep too well with the sound of my xbox coming out of the av gear

 

[unseen]

Could I not get away with using standard 100mm loft insulation? Where I could cut it more to fit the joists or is there a difference between say Knauf Crown Joist insulation to standard Wickes/B&Q loft insulation?

Any thoughts?

Rob

 

[shenks]

dinner will be in the dog on friday!

It could be worse... the dog could be in your dinner!
(this was once threatened to me although I didn't take it too seriously)

 

[unseen]

I went to pick up all the material today.... And got completely baffled about the insulation.. Unfortunetly I only tried B&Q and all they had was either standard rockwool (Knauf Crown), Crown Rafter 32 insulation or Knauf Crown DriTherm cavity insulation slabs.

Would the slabs work between the floors?? Or should I be looking at rockwool and trimming to fit? (And does anyone know why 100mm insulation is cheaper than 85mm?? Is it purely to make you buy the thicker stuff as it's better for the job??)

Any help as always appreciated guys!

Rob

 

[sunama]

Hi,

I just wanted to know if you have completed your project and if so how successful was it.

For reference, I did something similar. Details in the link below:
http://www.avforums.com/forums/showthread.php?t=396825