how to best sound attenuate the shed?

[Albert]

I am moving to another workshop, its not lined with anything and I would like to find out what is the best way to sound attenuate the noise from my machines.

the shed is as per below:

garage.jpg

I have quite a few machinery that makes a bit of noise, I am planning to put in the sound attenuating batts in the void and then a layer of sound proofing gib or similar material, does 2 layers of non sound attenuating gib works better or 1 layer of sound attenating will suffice?

any feedback is welcomed!

Cheers!

[Cliff Rogers]

Lining it with insulating bats behind the lining works best.

I also heard somewhere that gyprock lining is better than plywood for sound deadening but that isn't practical in a shed.

[BobL]

That looks like pressed metal sheeting as the walls, is that correct.

To attenuate the sound you need something heavy to keep the sound in the shed and then something "soft" to absorb the sound.

The "heavy" (or more accurately dense) can be something like thick chipboard or MDF or gyprock.
The "soft" can be acoustic batts or foam or even layers of cardboard.

Here is a useful table that compares the levels of sound absorption of different materials.
http://www.engineeringtoolbox.com/ac...tion-d_68.html
Note the effectiveness of plain old fibreglass rock wool so there is no need to fork out for expensive acoustic materials.

The other thing you need to watch out for are gaps as they do let out some sound.

My shed outer wall construction is also sheet metal. I used miniorb sheet metal over rock wool to line the metal working end of my shed and fibreglass under gyprock for the WW part of my shed. I was a bit worried about using the miniorb but it is surprisingly good as it is quite rigid and reflects the sound off at all different angles - problem is the price. I used gyprock for the woodwork part of my shed because I have shelves or cupboards lining these walls so I have no access to the walls to hand stuff on. OTOH as long as you know where the wall studs are I haven't found the gyprock to be a problem with hanging things on the walls.

[Albert]

That looks like pressed metal sheeting as the walls, is that correct.

To attenuate the sound you need something heavy to keep the sound in the shed and then something "soft" to absorb the sound.

The "heavy" (or more accurately dense) can be something like thick chipboard or MDF or gyprock.
The "soft" can be acoustic batts or foam or even layers of cardboard.

Here is a useful table that compares the levels of sound absorption of different materials.
http://www.engineeringtoolbox.com/ac...tion-d_68.html
Note the effectiveness of plain old fibreglass rock wool so there is no need to fork out for expensive acoustic materials.

The other thing you need to watch out for are gaps as they do let out some sound.

My shed outer wall construction is also sheet metal. I used miniorb sheet metal over rock wool to line the metal working end of my shed and fibreglass under gyprock for the WW part of my shed. I was a bit worried about using the miniorb but it is surprisingly good as it is quite rigid and reflects the sound off at all different angles - problem is the price. I used gyprock for the woodwork part of my shed because I have shelves or cupboards lining these walls so I have no access to the walls to hand stuff on. OTOH as long as you know where the wall studs are I haven't found the gyprock to be a problem with hanging things on the walls.

Thanks for that Bob, very useful info! cheers!

[ajwhi3]

Finally something I know about (I work as an acoustic engineer day to day).

There are two main things to consider; the build-up of noise within the shed (i.e. the reverberant noise level) and noise transmission to other areas (i.e. the wall/door/ceiling construction). If you are only interested in stopping noise transmission to other areas, you want to make a cavity wall that is well sealed (air-tight).

The best place to have a look would be the CSR Red Book as it outlines a number of constructions and their associated acoustic ratings (in Rw). The Gyprock Red Book - Gyprock

For a simple fitout, it would be best to decide if you would prefer plywood or plasterboard and create a decent cavity depth filled with insulation. The type of insulation will not have any effect on the wall performance, so go for cheap 10kg/m3 polyester or glasswool and ignore the rockwool.

Generally the weakest part of a building fabric is the door - so consider putting some seals on it if you don't have any, and remember if air can get through, sound can just as easily.

Cheers,
Adrian