Sound insulation

[JimK]

Tell us about the lead sheet "solution" ....:-)

Jim K

[Andy Burns]

Excellent thanks; three sheets of the 10kg/m^2 mat ordered and a local supplier for some 100kg/m^3 rockwool slab, 15mm acoustic PB, acoustic sealant, U-channels, C-studs and resilient bars.

Giving an extra 40kg/m^2 between me and their noise, £330 for the lot delivered.

[Andy Burns]

Went down to collect it yesterday, it certa> Sand is quite common for adding mass to floors (coffins). Bit more tricky

While I was there, I had a look at what other products they sold, one was a board made from a triple layer of stiff corrugated card, with the flutes filled with silica sand.

[Dave Plowman (News)]

I'm sure there are lots of alternatives. Which one is most cost effective for a particular job is the question as they'll all work on the same principle.

[Andy Burns]

That one seems to be pretty expensive (£36 for a 1200x800 board!) You could make it cheap enough if you could find a packaging manufacturer who would sell AAA flute corrugated in small quantities, or better still someone who receives items packed in the stuff ...

[Andy Burns]

phase 1 - removed all backboxes from the party wall, moved mains/aerial/sat/ethernet/phone sockets into chimney breast, also fitted three extra mains sockets from the ring while I was at that.

phase 2 - built frame from 38x44 timber

phase 3 - tonight I've fitted the rockwool into frame

That alone has cut a good slice of noise down, mainly the high frequency TV and chit-chat that were annoyingly noticeable.

Still got to fit the mass loaded vinyl - will need assistance from a different neighbour to hold it in place while it's stapled (that's why I changed from metal stud to timber) obviously need that neighbour not to let-on to the adjoining neighbour what I'm doing or they'll probably just turn the volume up if they think I'm sound "proof".

And then the plasterboard, so far so good, very hopeful the end result will be worthwhile (for that room at least).

[sorry about the dingy photo, the camera flash picks up a surprising amount of floating rockwool particles]

[dennis]

The BRE say you get better insulation if you suspend the rock wool between a false wall and the real wall, but you would need to move the partition in about 6 inches to do that.

I don't know if that would be true for mass loaded vinyl.

[meow2222]

That's a very light frame for soundproofing, hopefully the mlv will make it work ok.

NT

[Andy Burns]

I wanted to reduce the area of wood, so as to have a greater proportion of the cross-section occupied by rockwool, frames were screwed together laid flat on the ground and have metal corner plates for a bit of reinforcement - it wouldn't be enough for a partition wall, but it's plenty rigid for one running parallel to the real wall.

[Andy Burns]

Yeah when I set out, I decided I didn't mind losing 4" on one side of the lounge having just gained 3' on the other side by subsuming the hall.

From the different fitting guides I've seen you can either fit it between the real wall and the rockwool, or between the rockwool and the plasterboard, or between two layers of plasterboard, the 2nd option seemed simplest, no glueing just staple it to the studs.

I'll note how adding the different layers improves the performance, and try to gauge whether whether I'm willing to lose any space in other rooms, e.g. I might consider 35mm RW + 2mm MLV + 15mm PB in bedroom, compared to 50mm RW + 4mm MLV + 30mm PB being used in lounge - we'll see ...

[meow2222]

I reckon that's a nonadvantageous choice, sound transmission being affected much more by frame rigidity & weight than an extra inch of 'wool at the edges.

I'd have used 2x4 and sat 4" cement blocks on the noggings, then fill with rockwool. But its academic, with mlv you should get a good gain. 2 layers of PB will help with rigidity and less so mass.

NT

[Dave Plowman (News)]

Rockwool can help with high frequencies and to reduce reflections within your new structure, but isn't a particularly good attenuator on its own. Try putting some over your ear to hear the result. It's mass and air tightness that works best.

[sm_jamieson]

Seems the main advantage of the MLV is that it is heavy but also not rigid. So probably have the same type of affect as a sand-filled wall. Simon.

[sm_jamieson]

ake it work ok.

ed much more by frame rigidity & weight than an extra inch of 'wool at the edges.

h rockwool. But its academic, with mlv you should get a good gain. 2 layers of PB will help with rigidity and less so mass.

What you describe is more or less what I have around my soil pipe which pas ses through the kitchen extension.

I also did a soundproofing wall in the bathroom in the minimum of space. An inch air gap, then an inch of glass fibre reinforced concrete poured betwe en 1/2 inch cement boards (that were bolted together). No frame at all (exc ept a sole plate). To be honest I can't believe the work I went to. I think it works, but we have had no neighbours for a couple of years.

Simon.

[Andy Burns]

It's easy to get carried away.

Luxury! I look forward to mine being on holiday.

[Andy Burns]

OK the job is done, you may remember I opted for a minimal wooden frame spaced-off by 10mm from all existing floor/ceiling/walls, 50mm rockwool slabs, 5mm MLV sheet, acoustic/intumescent mastic all round, resilient bars with two layers of 15mm soundbloc plasterboard.

And the verdict is ... a success, the room is now getting ready to be decorated, but I can't keep resisting going in there to hear how quiet it is. The true test, I suspect, will be tomorrow's foo?ball.

Actually I'd say of the noticeable effects as each layer was installed, the MLV had the least effect, seemed to dull things somewhat. I'm wondering Adam, if you'd actually used it before, or just heard of it (no regrets in using it, just asking)?

Of course as I suspected, it raises the contrast to the other rooms with party walls, I might be tempted to do a "light" version at least in the main bedroom when its turn comes around - maybe 30mm rockwool, 2mm MLV, two layers of 12mm soundbloc on resilient bars.

[Adam Aglionby]

Seen,er, heard MLV in use, not really my area though , but its advantage ma y have been handling in the application, temporary sound blocking, easier t o remove than multiple layers of plasterboard and rockwool or in one case s ome years ago 7 tonnes of dry sand, didn`t have to have anything to do with removing that after...

Green glue type stuff seems to have following in building recording set ups with multiple layers of plasterboard.