Renovating large low ceiling room - Soundproofing options for the ceiling?

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Scoobymenace

9 posts

Wannabe Geek

#302993 9-Jan-2023 12:27

Hey! I'm currently in the process of renovating my first home and am in the process of getting the ceiling redone in the large room downstairs. The plasterboard / GIB has been taken down on the one side of the ceiling for the moment to expose the structural beams etc. I wish to make the room soundproofed so that I'm unable to hear things such as footsteps or moving of chairs from upstairs while equally making it so that upstairs cannot hear any form of talking or loud laughter / shouting from the downstairs and also music as well (Bass will probably be a compromise here due to costs to deal with it effectively)

Given the ceiling is low hanging (2.1m - 2.2m approx) I'm limited with soundproofing options which will encroach on the already limited ceiling height. (E.g. double GIB, tracks for decoupling etc).

I've also had a look around at insulation options and often Rockwool or Acoustic grade insulation pops up however, some insulation is labelled as wall insulation or ceiling insulation. Does this make any difference or will wall insulation work just fine in the ceiling and it's purely a marketing thing?

Would love to hear of any recommendations based off my situation from those of you who have the knowledge and thank you in advance :)!

Jase2985

13459 posts

Uber Geek

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Lifetime subscriber

#3018998 9-Jan-2023 13:33

any insulation will absorb sound

dt

1152 posts

Uber Geek
Inactive user

#3019060 9-Jan-2023 14:05

wall and ceiling insulation are different in thickness, ceiling being thicker for better insulating performance and must meet a minimum of R 2.9 for zones 1 and 2 and r3.3 in zone 3 in NZ.

I believe, but dont quote me on this, you can still use wall insulation in the ceiling but will need to double up to make up the difference in R value.

wellygary

8320 posts

Uber Geek

#3019063 9-Jan-2023 14:11

dt:

wall and ceiling insulation are different in thickness, ceiling being thicker for better insulating performance and must meet a minimum of R 2.9 for zones 1 and 2 and r3.3 in zone 3 in NZ.

I believe, but dont quote me on this, you can still use wall insulation in the ceiling but will need to double up to make up the difference in R value.

AFAIK there are no insulation requirements on Internal Walls/and or roof/floor spaces,

From what the OP said I believe that there is a upstairs floor above the ceiling that is being sound proofed?

If this is the case, then any insulation will be fine from a legal R Value requirement

dt

1152 posts

Uber Geek
Inactive user

#3019068 9-Jan-2023 14:36

wellygary:

AFAIK there are no insulation requirements on Internal Walls/and or roof/floor spaces,

From what the OP said I believe that there is a upstairs floor above the ceiling that is being sound proofed?

If this is the case, then any insulation will be fine from a legal R Value requirement

I completely missed that part and you are correct, no legal requirements there.

That being the case, without knowing at all what im talking about.. surely the wall sound proofing insulation should be fine then!

SomeoneSomewhere

1804 posts

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Lifetime subscriber

#3019115 9-Jan-2023 14:46

By memory insulation should be specified and fitted a bit different for sound deadening vs thermal - you want it quite heavily compressed (I remember hearing 2:1) for sound, whereas thermal insulation should be filling up all the space but as loose as possible.

A 'cheeky' solution to not having height for rails might be to put slightly-recessed dwangs/nogs between the floor joists above, then mount the rails to those. The idea would be to have the surface of the rails just proud of the floor joists, but so the gib isn't physically touching.

Do not underestimate the impact of having a good thick carpet and underlay on the floor above.

SomeoneSomewhere

1804 posts

Uber Geek

Lifetime subscriber

#3019116 9-Jan-2023 14:50

This is roughly what I remember doing. That's for horizontal transmission through ceiling spaces though, and vertical transmission is likely to be a bit different.

BlargHonk

147 posts

Master Geek

#3019117 9-Jan-2023 14:56

This Reddit DIYNZ thread might be useful

https://www.reddit.com/r/diynz/comments/ilgpvu/i_made_a_table_of_gib_noise_control_systems_and/

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itxtme

2102 posts

Uber Geek

#3019411 10-Jan-2023 08:43

Did this on an internal firewall in our old place. We didnt go crazy, ie. we did insulation (didnt have any) and acoustic gib but no rubber systems/isolation. That made an enormous difference. I would definitely get the noiseline (or equivalent) plasterboard. When you tap it you can feel the difference.

aucklander

477 posts

Ultimate Geek

#3020763 13-Jan-2023 09:47

noise transmission is reduced by adding mass. More mass will absorb more of the sound energy rather than allowing it to pass through. This is why the idea of compressing thermal insulation into the space, if only acoustic performance is needed. Thermal insulation works by using the trapped air, this is why is installed "loose" (not compressed). As mentioned, extra mass can be added by an extra layer of gib which would not impact too much on the ceiling height. This appears to be the easiest way and lower cost? Separating gib from joists definitely works better but might involve more cost. The resilient fixings are critical (rubber), any solid fixing will simply create a path for the noise to "leak" through.

https://www.eboss.co.nz/library/rondo-building-services/acoustic-wall-and-ceiling-systems