Stud Wall - he next Phase - Insulation!

[Thomarse]

Hi,

Having taken the advice from replies to my previuos posts, I am now building my new stud wall from 4x2" cls timber... And seeing as I am now going to be doing a "proper job"... I'd like to know the best way and the most costeffective way to insulate the wall, between the plasterboard sheets. Budget is an issue so I want to achieve good sound insulation for the minimum cost really.

Has anyone got any good suggestions of where to buy and what to avoid etc... I've had a quick look on Wickes as it was teh first site I found and saw the link below - I guess this is pretty standard, any pros and cons?

info gratefully recieved!

Tom

[Stuart Noble]

Standard rockwool is the cheapest. They say it's only for floors, but I don't see why. Mask and Marigolds are adviseable

[The Natural Philosopher]

Rockwool does slightly less than f*ck all for sound insulation, and in walls, it tends to fall down, which is why its not recommended for thermal much either.

If you wanted decent sound insulation you should have used blocks :-)

Make sure that every hole is taped and/or plugged with filler, and double up on the plasterboard..

[RobertL]

it's better to build it with staggered timbers so that there is no direct mechanical coupling between the board on each side.it means twice as much wood of course, and alsightly thicker wall. Fill the space with mineral wool (small effect). use double thickness of plasterboard both sides. caulk carefully at all the joins. It shoul give about 50-55dB attenuation at mid frequencies.

see ISBN 0-07-026942-4

Robert

[salesguy]

With respect, that is bollocks. Acoustic insulation in plasterboard partitions is either rock fibre, or more normally, glass fibre. The normal product used is Acoustic Partition Roll (APR) that is a high density glass matt.

Rock fibre can be used as well, due to it's higher densities.

As to cavities, correctly installed glass or rock will do the job, and will not sag or slump over time.

Boards are fine, but if there are *any* gaps the insulation is useless.

SalesGuy

[The Natural Philosopher]

Tell me what is HUGH DENSITY about rockwool.

Which is what I said.

[salesguy]

from 33kg/m3 to 200kg/m3.

That is high compared to glass.

My point above refers to thermal insulation - any gaps between foam boards render the insulation ineffective.

Mineral fibre (glass or rock) is the best acoustic insulant in this situation.

I agree block would be better, but that solution is hardly ever used for internal non-load bearing walls.

options.....

SalesGuy

[meow2222]

When people say budget is limited its hard to know how limited. 2 layers of PB on eahc side makes a more solid wall, and cuts out almost all the resonance.

The cheapest acoustic damping material is carpet scraps, but they are flammable.

Triple wall cardboard is quite good at acoustic damping. It could be cut out & stuck to the inner side of the PB on one side, though not both.

NT

[The Natural Philosopher]

No it isn;t. HF gets cut out by anything: There your main bugbear is micro airgaps. Seal properly and the HF is GONE.

LF is a different proosition. you want mass, without resonance. Frankly sand filling is as good as it gets for that, but doubled up PB is pretty effective.

More often than you think, especially with lighweight blocks.

[John Rumm]

Ecotherm (and I guess most of the others) do a PIR foam / cork laminate board for just this purpose. Its 100mm thick and offers good thermal performance with reasonable sound insulation as well. It looks like:

[The Natural Philosopher]

How can I say it loud enough

THERMAL INSULATORS DO NOT NECESSARILY MAKE GOOD SOUND INSULATORS AND VICE VERSA.

Since this is an internal wall, thermal insulation is IRRELEVANT..unless you want to create a refrigerated room, in which case anything inside will die of hypothermia, which will silence it anyway.

[dennis]

The BRE did say how to make a sound proof stud wall... You need two stud walls about a foot apart and hang mineral wall from the ceiling to the floor in the centre. Not as good as using blocks though.

[John Rumm]

Pay attention at the back, I never said they did.

The board I am describing is designed to offer good acoustic isolation as well as reasonable thermal insulation.

It has the cork (high density stuff - about 20mm thick) as one layer, and it also is covered on the rear side in a thick bitumen backed foil of the type typically used for sound deadening in cars. The PIR foam itself in the middle of the board is also pretty good at suppressing HF noise transmission. Each block also has significant mass compared with most insulating only materials.

You want to have rooms at different temperatures - for example a bedroom beside a bathroom as in my picture. Or where one room is subject to high solar gain and the adjacent one not, or when you may want them on different heating zones to match different patterns of use.