Thread: More shed sound insulation questions

I searched resilient channel Melbourne and these came up. There are more but theses will get you started.

Resilient Channel – Hume Building Products

https://atkar.com.au/product/resilient-channel/

Melbourne Building Supplies | Suspended Ceilings

Pete

The approach I took was timber framing, standard R1.5 batts and slatwall which gives you both the density (as its 18mm melamine mdf) and ease of hanging items with the aluminium extrusions. Stud spacing depended on where it was used, I have a mezzanine floor with joists at 450 centres so I put studs at matching centres, and 600 centres where it wasn't supporting the mezzanine loads. Framing used was 70x45, matching the depth of the steel purlins. So the total wall from the outside is Trimdek steel, fixed to 70mm tophat, which is fixed to a steel portal frame. Timber wall framing, outside wrapped in Ametalin, R1.5 batt, internal lining 18mm mdf.

This has proven to be reasonably effective, dropping sound levels by 6 to 8dB over the previous shed configuration depending on where it is measured from. From inside the house it is now unobjectionable, in fact I have passed WAF (wife acceptance factor). Which is really all you can ask for - it's a shed, they leak air, and if they leak air they leak noise too.

But don't forget it's not always how loud the noise is, but the frequency too. No matter what you do there are still conductive pathways. All common building materials have resonant frequencies. My biggest problem was not the things that were loud inside the shed like the table saw or planer thicknesser, but low frequency noise from the dust extractor vented outside. It only affected one neighbour, but it was bad - an unfortunate combination of distance, frequency, and harmonics.

Originally Posted by igalic

-Now finally for the questions
- on the inside, would I get any significant reduction in noise level if I used mdf or plywood instead of drywall? These would both be prohibitively expensive new, but people are often selling them cheap from packing or similar

They have about the same acoustic selection/absorbance characteristics so there won't be much difference - what really matters is how thick it is and how well supported it is ie stud spacing. ie 12 mm chipboard will be better than 10 mm drywall. BTW MDF is better than both drywall and chipboard.

- acoustic insulation batts are one of the most expensive items. I found some people on the forum suggesting that doesn't make a difference vs normal insulation (i.e. earthwool or similar). Is that true? Is there something more efficient I could do at the same or lower price? For example, normal insulation batts + 2 layers of drywall on the inside? Do brands matter?

Acoustic is definitely better than normal but not by as much as you might expect.

how have you all dealt with the roller doors? Should I just remove them and install normal doors in the frame?

Yes. Roller doors are basically hopeless at constraining noise.

Is there any better way? If building swinging doors, I'm also a bit concerned about the weight. Would the steel framing be able to support it? How do I check that?

In terms of sound insulation, does stud spacing make any difference? I.e. am I getting anything better or worse if using 430mm vs 580mm spacing?[/QUOTE]
smaler spacing should be better as increases wall mass and reduces any drumminess of the claddings.

to me achieving air-tightness seems hardest. I can put all this together, but I'm sure there will be gaps in many places. How do you deal with that in the easiest way?

Correct air tightness is critical and most shed owners weakest links. Using expanding foam, can help in awkward situations.

- with the above setup, can I realistically expect any significant noise reduction? Or am I going to be disappointed because it will still be way too loud?

The only way you can prove to yourself that you are making a difference is to use a sound meter. Get an app on your mobile phone and measure the SPLs at various points around the shed and repeat these as you make improvements.

Thanks for the help! It sounds like it makes sense for me to proceed the way I intended, though it's frustrating I can't know in advance if one option will be better than another. For example, I'm still not sure if it would be more efficient to go with normal insulation + 2 layers of drywall, or acoustic insulation + 1 layer of drywall. Trying it out is not really an option in the sense I can't install one system and then decide to go for something entirely different.

One more thing - considering my biggest concern is the neighbour whose terrace the garage is directly bordering, would it make sense if I made that wall better insulated than the others? For example, in addition to what I'll have elsewhere, add a layer of MDF boards on top, or use two layers of drywall just for that wall? The noise in my house is not so much of an issue, and all other neighbours are considerably farther away.

Another thing I have in plans is to house some of the tools in insulated enclosures, like the dusty, to help with noise too. But I can't do that for all tools so that's only going to be somewhat useful.

Regarding resilient channels, they do seem to come out at quite a bit. I'm not sure if it might make sense to do the DIY version I linked to, because I'm afraid I'll defeat their purpose with other things that will be an issue.


I'll post results once it's done

Acoustic batts are your best bang for your buck. You can buy acoustic plasterboard but it works out dearer per m2 and not as effective
Unless you particularly want plasterboard lining I would lean towards mdf or plywood

My Old shed was a steel 11/2 car garage. I lined the wall and ceiling with Earthwool ( I think R3 ) then lined everything with 12mm ply. At the time I got this from The Tile Importer in Oakleigh for about $12 for a 2400 x 1200 sheet. The result was that from about 2 metres the noise of the jointer and thicknesser would not bother anyone unless perhaps it was used at midnight. The other good thing was that the shed was a lot more pleasant to work in.

My new workshop is brick so not much of a guide for you but the dust extractor cubicle I built may be of interest. I have a Clearvue which sounds like a jet taking off so I built a 2000 x 900 enclosure using 70 x 35 pine studs and these were lined inside with plaster sheet, acoustic batts and 16mm MDF on the outside. This was a huge success as it dropped the sound of the extractor from 92db to 69db with all blast gates closed and 73db with two open. I was also able to fit my compressor and shop vac in the space.

A couple more 'helpful suggestions'
I have spent some time and effort reducing sound from an auditorium.
- if you possibly can, build your ' inside frame' isolated from the existing. Use rubber blocks or sheet as a separator. This prevents vibration being transferred to the outer skin.
-you can also get acoustic plasterboard, and firerated plaster board. The denser the better. Its noticeably heavier.
-you need a dense layer to block sound transfer.
Acoustic batts absorb a bit on the way through, and again when the sound is reflected back. Again, the denser the better.
-yes, airleaks also leak sound. Block them all especially on the neighbours side.
-if you have a dust extractor outside, you'll need to allow air in. Or it will all implode, or the extractor will suck all your tools out. [emoji16]
Well, you know what I mean.. Control where the air comes from. Use a baffle so there is no line of sight to the noise.

Pretty sure Boral or other plasterboard manufacturers have good brochures on noise reduction.
.


Russ

Originally Posted by igalic

Thanks for the help! It sounds like it makes sense for me to proceed the way I intended, though it's frustrating I can't know in advance if one option will be better than another. For example, I'm still not sure if it would be more efficient to go with normal insulation + 2 layers of drywall, or acoustic insulation + 1 layer of drywall. Trying it out is not really an option in the sense I can't install one system and then decide to go for something entirely different.

If are getting on the OCD side of this aspect of shed building/fitout and you have some materials available you can always make up a test box and put a loudspeaker inside the box and play back some machinery sound and measure the SPL outside the box. We did that the mens shed DC enclosure and it seemed to work. We quickly found out air gaps dominated the results and the final real structure was so leaky so we did not achieve anywhere near the same level of reduction we did with the box. But we didn't have to bother. Our nearest public is a school oval about 15m away and the kids are much noisier than the DC at that distance. The enclosure is about 70m away from the nearest shops but there's usually so much traffic and wind that the DC noise is barely above background at 30m away let alone at 70m.

I assume by dry wall you mean plaster? If so based on sound absorbance coefficients, here (https://www.engineeringtoolbox.com/a...tion-d_68.html) Dry is a much better reflector so it should bounce the sound back into the shed (more noise for you) but let very little will get through. Note the wide ranges provided for the acoustical absorbance because the values are frequency and installation dependent.

One more thing - considering my biggest concern is the neighbour whose terrace the garage is directly bordering, would it make sense if I made that wall better insulated than the others? For example, in addition to what I'll have elsewhere, add a layer of MDF boards on top, or use two layers of drywall just for that wall? The noise in my house is not so much of an issue, and all other neighbours are considerably farther away.

Its too hard to say - it depends so much on air gaps, frequency, reflections sheet metal support spacing, fixture method spacing, have you got any insulation in the roof?
You could try an experiment with your test box and scale down measurement distances accordingly. I doubt you will see much of a difference unless you have a precise SPL meter.
Either way it sounds like you may have to insulate your roof and won't putting double dry wall up there be fun. Acoustic bats will be much easier.

Another thing I have in plans is to house some of the tools in insulated enclosures, like the dusty, to help with noise too. But I can't do that for all tools so that's only going to be somewhat useful.

Apart from the dusty this is a RPITA for servicing and feeding timber in/out

Originally Posted by safari

I have a Clearvue which sounds like a jet taking off so I built a 2000 x 900 enclosure using 70 x 35 pine studs and these were lined inside with plaster sheet, acoustic batts and 16mm MDF on the outside.

May I please ask, what acoustic batts did you use please?

Got the acoustic batts from Bunnings.

https://www.bunnings.com.au/earthwoo...-pack_p0810602

Originally Posted by safari

Got the acoustic batts from Bunnings.

https://www.bunnings.com.au/earthwoo...-pack_p0810602

These earth wool acoustic/thermal batts at bunnings are one of about 6 different density acoustic/thermal batts manufactured by Earthwool.

The claim is:

Earthwool Acoustic batts can improve Rw ratings in wood stud construction by 3 to 5 decibels and in metal stud construction by 8 to 10 decibels, depending on the complexity of the wall configuration and the thickness/density. Earthwool Acoustic batts can be used for exterior and interior walls, floors, crawlspaces and a variety of ceiling applications.

I would expect to get similar performance in wood stud construction with almost any kind of glass wool insulation of comparable density and thickness.
As far as sound absorbance goes it's all about the pore density and the pore size. To reduce thermal transfer you want enough density of cells to prevent convention and as high a total batt thickness as possible.

These have a density of 20kg/m3 which puts then in Earth Wools "High density " range, not sure what others Bunnings sell but its easy to calculate by working on the volume occupied by an expanded pack and dividing that into the pack weight.

Higher density is better since it means smaller pore sizes so lots of tiny little bubbles of of air inside the pack to bounce the sound waves around inside to absorb more sound.

Earthwool do make a 24 and 30kg/m3 batts but you may have to go to specialist places or maybe Bunnings can do a special order.

In comparison, Bunnings R4 ceiling batts https://www.bunnings.com.au/earthwoo...-pack_p0810333 cost about $6 more for the same area coverage
These have around 1/2 the expanded density of the acoustical ones listed above - that's what generates their R4 versus R 2.5 thermal rating.
You could always pack the R4 batts into half the space and that will double the density and reduce the pore size so it should produce similar sound absorbance as the acoustical batts listed above - but you will lose thermal rating - well it certainly wont be 4 - it might well be 2.5! And pay $6 per pack more for the privilege

My guess is its all the same stuff with the glass fibres spun to different thickness and maybe the acoustic ones use an additive to increase the density of the glass. if you are are interested in heat control then just use the thermal ones - they will reduce a lot of sound anyway. If you are interested in noise reduction then us either acoustic ones as they will reduce heat ingress to some extent anyway.

The selection and use of acoustic batts are as you sound like you know by far the not the end of the noise story. The gaps are critical followed by the cladding and structure you use. If you use a high mass internal cladding with narrow studs spacings this should reflect most of the sound back into the shed so the batts will have to do very little work in absorbing the remaining transmitted sound. The thickness of Plaster board or MDF on narrow studs will then be the deciding factor. Inside the shed reflected sound can be reduced by scattering so the texture of the internal cladding makes a difference.

In the metal work part of my shed for fire prevention purposes clad the walls used 2.4 m long miniorb. Because it is so stiff and self supporting I did not use any studs - I just filled the wall gap with R2 rockwool. I had read about how good miniorb was at reflecting and scattering sound but If I had known how effective it was going to be in practice I would have clad the whole of the inside of the shed with it. It's a pig to install as everything has to be kept absolutely square. If sufficient fixtures are used to attach the minicab to relatively heavy stuff can still be hung off it using tek screws but of course holes are not as easily repaired.

A couple of things I forgot to mention, the wall stud spacing matters for thermal insulation too. A 90x45 stud has an R value of about 1, at 450 centres this means 10% of the wall has that R value. As your shed is steel frame which is load bearing, 600 centres will save you material and is more thermally efficient.

As Bob mentioned, you can use thicker thermal batts and pack them in which will reduce their thermal rating but may improve acoustic performance. I would only go one size up, say if your studs are 70 then use 90 batts. As these are compressed in packaging, you should be able to take them out of the pack and fit them straight in the cavity, without bouncing them on edge to expand the fibres as you normally would. If you find acoustic batts hard to get, it's an alternative.

The other thing I forgot was that where I have benches fixed to walls, I have lined the wall to 1200 high with recycled 6mm FC sheet, there is no point using thicker cladding where you have a permanent object in front of it which will absorb/reflect sound. Cupboards do make a difference, I've recycled kitchen cabinets and the noise level dropped again once these went in as you'd expect with 16mm mdf doors and 16mm chipboard carcase.

My Old shed was a steel 11/2 car garage. I lined the wall and ceiling with Earthwool ( I think R3 ) then lined everything with 12mm ply. At the time I got this from The Tile Importer in Oakleigh for about $12 for a 2400 x 1200 sheet. The result was that from about 2 metres the noise of the jointer and thicknesser would not bother anyone unless perhaps it was used at midnight. The other good thing was that the shed was a lot more pleasant to work in.

My new workshop is brick so not much of a guide for you but the dust extractor cubicle I built may be of interest. I have a Clearvue which sounds like a jet taking off so I built a 2000 x 900 enclosure using 70 x 35 pine studs and these were lined inside with plaster sheet, acoustic batts and 16mm MDF on the outside. This was a huge success as it dropped the sound of the extractor from 92db to 69db with all blast gates closed and 73db with two open. I was also able to fit my compressor and shop vac in the space.

That's very enouraging, I think if I could get to that level I'd be very very happy.

Originally Posted by BobL

Its too hard to say - it depends so much on air gaps, frequency, reflections sheet metal support spacing, fixture method spacing, have you got any insulation in the roof?
You could try an experiment with your test box and scale down measurement distances accordingly. I doubt you will see much of a difference unless you have a precise SPL meter.
Either way it sounds like you may have to insulate your roof and won't putting double dry wall up there be fun. Acoustic bats will be much easier.

Apart from the dusty this is a RPITA for servicing and feeding timber in/out

The sound box is not a bad idea, although I'm not sure how much I'd trust my measurements from that. As you said the shed would differ quite a bit from that construction. Still might give it a go.

Regarding the roof, I was planning to do the exact same thing as with the walls, just without the cement sheet on top. So, acoustic batts plus lining below that.

For enclosing machines, dusty was the main one, but other than that I was thinking maybe router table (I've got the Sheppach one with in-built lift so I don't need access from below). The rest I don't think I'd have much success with.

Originally Posted by BobL

These earth wool acoustic/thermal batts at bunnings are one of about 6 different density acoustic/thermal batts manufactured by Earthwool.

The claim is:

I would expect to get similar performance in wood stud construction with almost any kind of glass wool insulation of comparable density and thickness.
As far as sound absorbance goes it's all about the pore density and the pore size. To reduce thermal transfer you want enough density of cells to prevent convention and as high a total batt thickness as possible.

These have a density of 20kg/m3 which puts then in Earth Wools "High density " range, not sure what others Bunnings sell but its easy to calculate by working on the volume occupied by an expanded pack and dividing that into the pack weight.

Higher density is better since it means smaller pore sizes so lots of tiny little bubbles of of air inside the pack to bounce the sound waves around inside to absorb more sound.

Earthwool do make a 24 and 30kg/m3 batts but you may have to go to specialist places or maybe Bunnings can do a special order.

In comparison, Bunnings R4 ceiling batts https://www.bunnings.com.au/earthwoo...-pack_p0810333 cost about $6 more for the same area coverage
These have around 1/2 the expanded density of the acoustical ones listed above - that's what generates their R4 versus R 2.5 thermal rating.
You could always pack the R4 batts into half the space and that will double the density and reduce the pore size so it should produce similar sound absorbance as the acoustical batts listed above - but you will lose thermal rating - well it certainly wont be 4 - it might well be 2.5! And pay $6 per pack more for the privilege

My guess is its all the same stuff with the glass fibres spun to different thickness and maybe the acoustic ones use an additive to increase the density of the glass. if you are are interested in heat control then just use the thermal ones - they will reduce a lot of sound anyway. If you are interested in noise reduction then us either acoustic ones as they will reduce heat ingress to some extent anyway.

The selection and use of acoustic batts are as you sound like you know by far the not the end of the noise story. The gaps are critical followed by the cladding and structure you use. If you use a high mass internal cladding with narrow studs spacings this should reflect most of the sound back into the shed so the batts will have to do very little work in absorbing the remaining transmitted sound. The thickness of Plaster board or MDF on narrow studs will then be the deciding factor. Inside the shed reflected sound can be reduced by scattering so the texture of the internal cladding makes a difference.

I found 20kg/m3 acoustic batts that come out to about $6/m2, which is pretty good. I don't think I could beat that by trying to compress normal glass wool.

Originally Posted by richmond68

The other thing I forgot was that where I have benches fixed to walls, I have lined the wall to 1200 high with recycled 6mm FC sheet, there is no point using thicker cladding where you have a permanent object in front of it which will absorb/reflect sound. Cupboards do make a difference, I've recycled kitchen cabinets and the noise level dropped again once these went in as you'd expect with 16mm mdf doors and 16mm chipboard carcase.

I'm leaning more towards the idea of using MDF for lining. I can't find affordable plywood, but I've found a few places that sell cheap MDF (around the same price as plasterboard) at 12, 16 or 18mm. That will give me a lot more mass than plaster, so hopefully will give better sound insulation. Then later if I want to reduce sound reflection inside, I might put something soft (like rubber) on the floor, or sprinkle carpet tiles on the walls - ugly but will probably help.

With the MDF sheets, the issue I have now is all I've found are large 3.6m x 1.6m ones which are quite heavy so I'll have a hard time hauling them over. I've also found smaller ones (1.2m x 0.6m), but that means a lot more joint lines which I'm not sure how to fill. I had the idea of cutting strips of the same MDF and gluing them on the joint lines as "gap filler" - again a bit ugly but if the whole workshop is done that way it will look like decoration Just thinking out loud...

Again thanks everyone for ideas, I'll start gathering supplies and plan to start in about three weeks.

Originally Posted by igalic

Then later if I want to reduce sound reflection inside, I might put something soft (like rubber) on the floor, or sprinkle carpet tiles on the walls - ugly but will probably help..

These are all trip and dust traps and carpet is a notorious dust maker. None will do a cracker about sound direct from a machine to your ears - and you should be wearing muffs with machinery anyway. If you have enough variety of angular surfaces as most sheds do, this scatters the sound around quickly enough and it will absorb in the air itself.

One of the benefits of using miniorb was no join work was needed but the plaster board was a PITA. Next time I build a shed I would use MDF and put minimal effort into the joins.I'll just run a bead of sealant along the joins and even leave the screws showing. Then if I want to remove a sheet it's dead easy to do. 2.4 x 1.2 m sheets are a reasonable size to handle and even the 1.2 x .6 would be fine, by the time you get cupboards, shelves, ducting and machinery around the place you don't tend to even notice the walls and they all help reduce the noise.