Soundproofing timber frame

[geraldthehamster]

Can anyone give me some advice, please, on soundproofing, during construction, the exterior walls and ceiling of a single-story timber framed extension, to keep out traffic noise from outside?

The exterior walls will consist of timber frame, insulated to regs, but clad externally in timber (cedar or chestut), ie with no brick leaf or cavity. The roof will be a warm roof covered in EPDM.

Last year I designed and built a front porch along similar lines - from the inside out: skim, plasterboard, 25mm Celotex, 4x2 frame with Celotex infill, OSB, blue fabric, battens, cedar cladding. It's quite noisy.

I have also renovated the first floor of my dormer bungalow using double plasterboard (one of which was Soundbloc) over 25mm Celotex over and 100mm between the rafters, and the result wasn't satisfactory from an acoustic point of view. I want to do better for the extension.

I want to add mass (which is, in principle, lacking), using Soundbloc plasterboard and dense quilt or acoustic batts, and possibly also some acoustic separation - should I be thinking in terms of creating an entirely separate frame a couple of inches inside the structural frame (perhaps out of 2x2), and filling the gap with quilt? Or is there a more standard method? I don't want to try to reinvent the wheel. Does anyone have any experience? It's construction details and the order of things that I need.

Cheers Richard

[Martin Brown]

I have found the compacted rocksill wool sheets approx 150cm x 100cm x

4cm officially sold I think as cavity wall insulation pretty good as acoustic damping inside an interior timber and plasterboard wall.

You may need to be more careful about vapour barriers on an exterior wall to avoid condensation problems.

[Dom Ostrowski]

Chapter and verse here in PartE of the approved documents:

think you'll be looking at independent studwork. These don't have to be double thickness, one face can be interleaved with the other face, and the noggins set on edge - but no contact points between the two faces, and a continuous layer of sound insulation weaving in and out between them.

[geraldthehamster]

ce, please, on soundproofing... Chapter and verse here in PartE of the appr= oved documents:

I think you'll be looking at independent studwork. Th= ese don't have to be double thickness, one face can be interleaved with the= other face, and the noggins set on edge - but no contact points between th= e two faces, and a continuous layer of sound insulation weaving in and out = between them.

Thanks. I didn;t think to look at Part E, and as you say, some useful infor= mation there. It does deal with walls within buildings rather than external= walls, though the principles are going to be the same where airborne sound= is concerned.

Cheers Richard

[sm_jamieson]

What do they do with actual timber framed houses? In this country they are often brick clad, but what about the "noisiness" of timber framed houses used around the world? Anyone know? Simon.

[meow2222]

[geraldthehamster]

Thanks. We're still talking about interior partition walls though. I don't know to what extent the technical aspects differ for external walls. Probably not a lot; sound is sound, I guess. Though within a building there is also vibration to contend with, whereas from the outside it's mainly airborne sound. I'm keen on the staggered stud approach, though it does increase my materials costs ...

Cheers Richard

[David WE Roberts]

We have just added soundproofing to a party wall, and it has certainly made a difference. As you suggested, we had a stud wall built out of 2*2 with the gaps between the studs filled with rockwool batts. The major sound proofing comes from the 2" air gap between the stud wall and the original wall. This is allegedly better than filling the void with any sound insulating material.

We effectively have a hidden room 2" wide :-)

Oh, and the facing was OSB then plasterboard so it is easy to screw brackets and stuff to it without having to locate a stud.

Cheers

Dave R

[geraldthehamster]

I would have thought that the mass of mineral wool or similar would be more effective, but I'm open to being convinced otherwise. As long as you don't fill it with anything that will transmit vibration.

Ideal for people of the small furry squeaky persuasion :-)

The OSB will be contributing to the sound-proofing mass as well.

Cheers Richard

[meow2222]

Sound is vibration. The principles are the same, the lowest frequencies are attenuated less by damping, so concentrate on mass for that. Thermal insulation can damp vibration & resonance as well as insulate.