Sound insulation of soil pipe

[Owain]

"Lobster" wrote | I want to apply sound insulation to an internal soil pipe, which runs | vertically from ceiling to floor. I've built a timber frame around it, | which I'm going to cover with two layers of 12.5mm plasterboard and | have skimmed. I know the ideal way would be to fill the boxing with | sand to deaden the sound, but that would cause too much grief (can't | quite imagine filling up all my boxing - which has to be quite | large - with sand; plus there's a rodding eye at the base for which | access is needed). So I propose to fill the void with Rockwool.

Sounds good. Esp if the pipe is plastic, I'd suggest stiffening it by glueing some of those deadening felt panels used in loudspeaker cabinets around it. Probably won't need to be completely covered, but should deaden the noise of upstair's turds flowing down inside the wall as you're trying to enjoy a radox moment.

Alternatively/as well, box round the rodding eye and then fill the cavity with e-x-p-a-n-d-i-n-g foam.

Owain

[Peter Taylor]

Owain wrote

OMG that needs rewording. Whatever you do, don't FILL it!!! It only needs a little - just enough so that it's filled AFTER the foam has expanded otherwise a disaster awaits. (Read the FAQ) ;o)

Peter

[Philip Roberts]

I've never used it, but there is plasterboard that it designed to work as a sound check (a bit like the fire check plasterboard) there might be some info on the lafarge website.

Have fun

Phil

[Dave Liquorice]

Don't forget access, not just for maintenance you mention a rodding eye but you also have a hand between floors cable duct for phone, network, TV etc. It almost certainly runs from roof space to ground floor as well...

TBH two layers of 12.5mm plasterboard are going to do far more than a bit of rockwool no matter how much or little you put in. Make sure that there are no holes/cracks for the sopund to sneak through as well. Stagger and board joints buy as much as possible indeed I'd be tempted to seal the edges of the lower layer of board before putting the top layer on and seall all those edges as well.

Worth looking at I would have thought or maybe some heavy matting to sandwich between the PB layers.

[Peter Parry]

If you are using double plasterboard the rockwool will make no appreciable difference. What will make a difference is making sure every single joint in the boxing is perfectly sealed and airtight. If you want to use a filler there is a variety of Rockwool made in slabs rather than rolls deigned for noise insulation in stud partition walls. That is likely to have more effect than insulating material.

[Huge]

[14 lines snipped]

I've also found it's helpful to blow out the tube on the top of the aerosol can with an air line before the foam sets. Be careful where it goes, though...

[Owain]

"Lobster" wrote | Thanks to Owain for the suggestion about using speaker wadding; | a good idea too although I wonder if it would it be much better | than Rockwool (given that I already have the Rockwool and would | have to source and buy the acoustic wadding!).

Not wadding (which is what the rockwool will do) but heavy felt panels stuck to the pipe to reduce resonance and stop the pipe sounding like a digeridoo. They're stuck to the inside of door panels in cars etc to dampen vibration.

Owain

[Lobster]

I want to apply sound insulation to an internal soil pipe, which runs vertically from ceiling to floor. I've built a timber frame around it, which I'm going to cover with two layers of 12.5mm plasterboard and have skimmed. I know the ideal way would be to fill the boxing with sand to deaden the sound, but that would cause too much grief (can't quite imagine filling up all my boxing - which has to be quite large - with sand; plus there's a rodding eye at the base for which access is needed). So I propose to fill the void with Rockwool.

Question is - should I insert Rockwool in it's 'natural' state, ie, unpack the stuff and let it expand to its maximum, and not allow any compression when I put it round the pipe (which I know would be best if I was dealing with thermal insulation here), or should I cram as much Rockwool into the void as I possible can? Would that be better/worse/similar to option 1? The stuff is pretty dear, so I don't want to overstuff the boxing if it's not going to be beneficial.

Thanks David

[Ian Stirling]

The absolute best improvement you could probably get (other than sand) would be to decouple the two layers of plasterboard from each other a bit. This would stop sound travelling directly from one to the other. I don't know the architecture, but would putting the first layer of plasterboard on, and then building a second structure, only connected to the first at top and bottom around it, on which the second layer is connected be possible?

[Christian McArdle]

I bought a brand that came with 2 different size nozzles. You get 2 goes without having to clean. Now if someone comes out with a can with 5 nozzles attached to the side, I'll be happy. Life is too short to clean those little b*stards.

Christian.

[Dave Liquorice]

So did I on the basis it was the same price as another brand with only one nozzle...

Wait until it's cured, roll the tube between your hands squidging it slightly unscrew from the trigger bit and the foam will just pull out. Small screw driver will dig/push the rest out of the trigger half.

[Andy Hall]

So you might not use all the can, and next time need to buy another.......

.andy

To email, substitute .nospam with .gl

[Lobster]

compression

That's a good thought; however the BCO has already decreed the use of two layers of plasterboard (as being equivalent to fire-check board which my application needs, for reasons I won't go into here.)

Thanks to Owain for the suggestion about using speaker wadding; a good idea too although I wonder if it would it be much better than Rockwool (given that I already have the Rockwool and would have to source and buy the acoustic wadding!). I think I'll pass on the expanding foam - bit too 'permanent' for my liking; if it turns out not to work as well as hoped I'd be stuffed.

Can anyone comment on my original Q above - how much Rockwool to use?

Cheers David

[N. Thornton]

Or perhaps glue on a layer of under-laminate-floor 3mm sound absorbing sheet, then glue your last PB layer onto that. Dont screw through it, as that will largely defeat the working of the mat. Note I havent tried this. Also note that each measure will help some, so a combination of approaches is what will produce best results.

Regards, NT

[Bill]

In message , Lobster writes

I used it a year or so back and found it a pleasure not to have to keep worrying about keeping the nozzle clear. It was simply a matter of putting some of the cleaner through to remove any residue. That said the cleaner did leak a bit when attached to the gun.

On a rather amusing note I did some work for my 84 year old father last month and used a small amount of foam from a rather large can. Not having a use for the rest of the can I put it in the bin as I had no expectation of it lasting until it may be needed again. Any father remembering that you should not put pressurised containers in the bin decided to release the pressure by piercing the can with a garden fork. Apparently it was quite spectacular!!!!!!!!

[Owain]

"Bill" wrote | And father remembering that you should not put pressurised containers | in the bin decided to release the pressure by piercing the can with | a garden fork. | Apparently it was quite spectacular!!!!!!!!

How many cans would I have to conceal in my wheeliebin to give the crusher on the bin lorry something to think about?

Owain

[Lobster]

I agree - or why don't they sell spare nozzles...?!! I'd happily buy them in packs to avoid cleaning them up. When I bought some recently at Wickes I actually had a job finding a can with a nozzle attached, presumably because others had helped themselves to 'spares' to use on half-used cans.

Incidentally I notice that as well as conventional cans, Screwfix do 'gun grade' foam (ref 18821) plus a gun (ref 14315) and foam cleaner (ref 12040). Has anyone tried this? Or is it just a lot of hassle compared with normal aerosols and disposable applicators?

David

[Jerry Built]

I agree - however, I would still pack in some rockwool, it might help dampen vibration in the pipe. Maybe ruberoid/capping felt would help (*messy*)!

Very important.

J.B.

[Lobster]

Thanks for this; all sounds very sensible and have done all the above today. After reading this and the other replies I decided that my access panel was likely to negate much of the good work, so after much thought I've made this only "semi" removable, in that it has three layers - MDF innermost, which nestles snugly within the timber studding; then a larger square plate of plasterboard (about 0.5" larger all round); then a second plasterboard plate, 0.5" larger all round than the first. I carefully cut the two plates out from the plasterboard I used for the actual boxing in, so they are a precise fit. When the panel is inserted into the matching hole, it's flush on the outside, and there is therefore a double-stepped interface to prevent sound leakage. The plan now is for the plasterer to skim over the whole lot, and he'll just score a line along where the gap is, to define the edge of the panel (held in by dome-capped mirror screws). In the unlikely event of my ever needing to access the rodding eye (I've never needed to do so before in my life!) I'll have to break the plaster seal, but meanwhile, the soundproofing should be pretty good.

Sounds a good one but the BCO specified two back-to-back layers of PB to give the requisite amount of fire protection (BCO isn't concerned about the noisy turd issue!)

David