ceiling soundproofing

mattym

Banned
Soundproofing a ceiling is the same priciple as soundproofing a wall, same materials apply

suspended ceilings can be effective in soundproofing as well as acoustically treating a room, but it depends on how much space you have to loose in the room
 

HCK

Active Member
try this site, they have some good articles on sound proofing.

http://www.customaudiodesigns.co.uk/

I am in the process of converting my cellar and do not have the height for a suspended ceiling. I have put between the joists some acoustic quilt and mineral wool.. I also siliconed between the floorboards and this stops any travelling air.
 

sunama

Active Member
Today, i checked my ceiling (i bought the property 3 days ago) and it is a suspended ceiling. It has a 13cm gap.

My question is this: should i choose the cheap option and just fill the gap up with loft insulation (or acoustic quilt)?

OR

Should i have the original ceiling (which is above the suspended ceiling) padded out with extra plasterboard, resilient bars, battens and green glue and then have a brand new suspended ceiling put in below that, filling the gap up with loft insulation (or acoustic quilt)?

Also due to pricing, is acoustic quilt really that much better than ordinary loft insulation for sound proofing purposes?
 

HCK

Active Member
hi,

It would be hard to say but acoustic quilt has a layer or compressed rubber in between the insulation......so it maybe better but without testing it cant be proved!!
 

sunama

Active Member
Right i think i know what i can do with this suspended ceiling:

I have a gap of approx 130mm.
Im gonna fill 100mm of that space up with Acoustic Mineral Wool Slabs. I will use 100mm thickness (so that still leaves an air gap). Im thinking of using either 80kg/cubic meter or 100kg/cubic meter. Ive requested quotes for a price on these items. My ceilling measures 19.65 sq.m.

My thinking is that 100mm of thick, dense material will go someway to reduce the noise that my home cinema setup will send out to my upstairs neighbours.
 

Londondecca

Active Member
My current plan is to fill between the joists and add another layer of plasterboard with some Green Glue.

For more ideas have a look at the AVSforum site
 
B

Brian Ravnaas

Guest
hi all,

you'd want to opt for the lowest density insulation for filling the cavity. while denser types have some advantages as sound absorbers, they have an adverse effect on low-freq performance relative to their lower density types. indeed normal boring fiberglass has done as well or better than any insulation when used in walls.

so, my vote is "NO" acoustically specialized insulation is not better inside walls, and may well be worse, i'd be happy to dig up some data on all of these points should anybody require it. All that noted, always look for comparative tests. If somebody could demonstrate that over the whole freq range something had advantages that would be cool, but in all the data of which i'm aware, lower density common types do best at low freqs


In any case, the ceiling is a good place for resilient channel (resilient rail/resilient bars) as the air cavity is very deep (resilient things like alot of air space, helps lower resonance poitns to improve low-freq performance), and certainly an improved ceilign would help your cause.

good luck
 

sunama

Active Member
Would the same advice be true of walls? My main problem is that i want to protect my upstairs neighbours from my noise. I dont care about their own noise, just my own. The problem right now is that higher frequencies (not bass) travel between upstairs and downstairs very easily. This is why i want to get a thick, dense material but upstairs and downstairs. The loud bass will only be played during the daytime, so i dont really care if that travels upstairs. But i may watch movies at lower volumes/bass levels at night, so i at least want to prevent them from being disturbed by the sound of mid to high frequencies.

I have no intention of doing anything to the walls.
 
B

Brian Ravnaas

Guest
sunama said:
Would the same advice be true of walls? My main problem is that i want to protect my upstairs neighbours from my noise. I dont care about their own noise, just my own. The problem right now is that higher frequencies (not bass) travel between upstairs and downstairs very easily. This is why i want to get a thick, dense material but upstairs and downstairs. The loud bass will only be played during the daytime, so i dont really care if that travels upstairs. But i may watch movies at lower volumes/bass levels at night, so i at least want to prevent them from being disturbed by the sound of mid to high frequencies.

I have no intention of doing anything to the walls.
hmmm... if high frequencies are the primary type of sound-leak, then i would focus first on flanking noise.

typically seal problems manifest themselves most severely at higher frequencies, and the same can be said for the noise leaking through ductwork. In general, its reasonable to assume that at low freq's a wall or ceiling construction is what is failing you, but at high frequencies generally even a fairly mediocre floor/ceiling or wall can do the job adequately.


With respect to choice of insulation, if middle/high freq's are problematic, it is very likely that the problem can't be solved by insulation alone, but that some type of direct air path has to be found. A seal failure, or a ventilation duct would be the things that i'd look for.

To shed some perspective on how much denser type insulations can help, the attached graph shows NRC, Canada measurements for different insulations. A few decibels are gained when moving to the higher density insulation at middle/high, but the most important point is that either assembly has 40-60 dB of isolation at middle/high freq's, which should be a good level of isolation for even fairly loud movie watching.

those ceilings were normal 2x10 joists (240mm deep wood joists) with 16mm drywall on resilient channel for the ceiling and 15mm wood on the floor above, just different insulation, which was ~8" / 210mm of either fiberglass or mineral fiber. data shared with NRC permission.


Hence, before worrying about which construction to choose, i'd try to track down something that was leaking sound easily/badly - seal problem or a culprit duct.
 

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sunama

Active Member
I cant believe that there is some duct or space that is allowing sound to pass through the ceiling/floor boards. The upstairs people have wooden floors which obviously dont insulate against sound. The same problem is in my bedroom.

Anyway i now have quotes of the costs involved. The sound proofing in my bedroom will involve the original ceiling; below it will be 10cm of sound proof quilt; below that a layer of sound board; below that another layer of soundboard (the 2 layers of soundboard will sandwich some green glue). This will be done to my bedroom ceiling in order to protect me from the neighbours' noise (including impact noise).

The lounge (home cinema room) will have below the existing ceiling, 10cm of mineral wool (density of 80 or 100kg/sqm); below that will be ceiling tiles (suspended ceiling) - the ceiling tiles will have 1 layer of plasterboard above them, sandwiching a layer of green glue.

To carry out the above to the rooms will cost approximately £1k per room.
 

mattym

Banned
sunama said:
I cant believe that there is some duct or space that is allowing sound to pass through the ceiling/floor boards. The upstairs people have wooden floors which obviously dont insulate against sound. The same problem is in my bedroom.

Anyway i now have quotes of the costs involved. The sound proofing in my bedroom will involve the original ceiling; below it will be 10cm of sound proof quilt; below that a layer of sound board; below that another layer of soundboard (the 2 layers of soundboard will sandwich some green glue). This will be done to my bedroom ceiling in order to protect me from the neighbours' noise (including impact noise).

The lounge (home cinema room) will have below the existing ceiling, 10cm of mineral wool (density of 80 or 100kg/sqm); below that will be ceiling tiles (suspended ceiling) - the ceiling tiles will have 1 layer of plasterboard above them, sandwiching a layer of green glue.

To carry out the above to the rooms will cost approximately £1k per room.
crikey oreilly.
 

Beaker

Active Member
How much of that £1k is materials and how much is labour? I suppose it depends on how handy you are but you can buy all the stuff from a builders merchant, Knauff and British Gypsum both make a sound proofing plaster board. One of them is pink in colour. You need another pair of hands to dry line a ceiling, but if you can use an electric screwdriver and a Stanley knife it is all really quite easy. If you put up a shelf then you can do this yourself and spend the money or more important stuff like AV kit.
 

sunama

Active Member
Well, the guy who quoted me this price, included his (and his workmen's) labour as well as materials. It includes 2 layers of soundboard and acoustic quilt. The green glue i will have to order in and supply myself. Although, upon asking around, i feel that rather than acoustic quilt, dense mineral wool slabs would be better. Also, ive been advised that it may be better to take down the existing ceiling and start fresh, lining the dense mineral wool between the joists (due to its weight).

I can put up a shelf with ease, however, i have no idea how to take down a ceiling and install a new one. I wouldnt even know where to begin.

Alot of my materials are coming from www.screwfix.com and they dont sell plasterboard or sound boards. I'm open to any advice here as i would prefer to do it all myself (to save costs).
 

Beaker

Active Member
No Problem. I'm at an advantage perhaps as I've spent the last two years renovating and extending a 1932 semi. I've taken the house back to the bare bones, no plaster on the walls or ceilings and I've done a lot of the work myself to save money.

If it is an old ceiling, like mine, it will be plaster containing stuff like horse hair as a binding, which was pushed onto a load of thin wooden planks called lattes, or laths not sure which. The soft plaster squidged between the lattes and formed a mushroom on the other side which holds it up.

If it is a newer build or had the old ceilings replaced then it will probably be plasterboard.

My experience, you will need a hammer, claw or better a crow bar as it is heavier. You will a good dust mask I use 3M ones and some old clothes. Better get one of those white disposable suits they never were in CSI when doing a crime scene. Some masking tape to seal round the door whilst you’re inside wrecking the place and it will be dusty.

Make a hole on the ceiling, but the hook of the crow bar through it and pull down. It really is that simple but it makes a big mess. Obviously be careful around the light fittings

You will also need a bath afterwards if it was anything like my house.


Knauf make a sound blocking plasterboard http://***********/z9fr9 you might even be able to get it at Wickes but somewhere like Builder Center sell it. http://***********/kejru is the equivalent made by British Gypsum.

To cut it your score along your cut line and then bend the plaster board along the cut, but a length of timber underneath to give some height. This will split the board, you then need to cut the paper on the other side to separate the two bits.

I find drywall screws much easier than nails to dry line with but you will some one to help oir hire a board lifter http://***********/h7rde .

Have a look around the Knauf website, you will find Acoustic wall batons and the like. Also look at http://***********/gqj89 which explains the building regs, not so much that you need to adhere to them in your case but it will some guidance. Here is another good guide on Part E http://***********/equpf .
 

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