Soundproofing a floor

[donlogan]

Hi, i'll soon be rewiring my house.

As it's all chipboard upstairs, i'm gonna pull it all up and lay new chipboard once the rewiring's done. As i'll have the floor up, i want to get some soundproofing in there as the main bedroom is right above the lounge and you can hear people's voices from below, pretty much word for word.

Has anyone had any experience of doing this on the cheap?

I had a few ideas:


Stick loft insulation between the joists in the floor.

Cut polystyrene sheet to size and stick that in there, maybe seal edges with expanding foam or acoustic sealant.

Buy proper acoustic mineral wool stuff and stick that in there (not likely as it's not cheap).


Whatever i do, i'll get some decent underlay and carpet fitted which should help. I could probably chuck a maximum of 500 quid at whatever i do to soundproof as long as it works.

What do people reckon?

Thanks.

 

[Whitespirit66]

I'm no expert in these matters, but you will need to think about putting thin deadening material between the top of the floor joists and the new flooring.

You're right to insulate the gaps between the joists, but that's only part of the problem. All noise is just vibration. This noise/vibration will be collected by the lounge ceiling, and transmitted through the joists to the floor above.

Not sure what to use, you may have to do some research. possibly some thin sheet rubber. Alternatively, you may be able to get special flooring with an acoustic backing.

 

[joe-90]

Thick carpet and underlay is good.

 

[pred]

Instead of pulling up the floor boards bring the ceiling down its a lot easier to rewire and run central heating pipes, then fit sound proofing plasterboard,

http://www.soundservice.co.uk/acoustic_plasterboard.html

 

[Whitespirit66]

Thick carpet and underlay is good.

Yes, a good 70s sh@g pile should do it.

 

[flameport]

Loft insulation won't do much. Polystyrene will be totally useless, and will damage any cables it is in contact with.

The first thing is to make sure there are no gaps or cracks in the ceiling as even a tiny hole will let a lot of sound through. Where cables pass through the ceiling for a light etc., the hole should be sealed with mastic.
If you have downlighters, they will need appropriate covers sealing over them.

If the walls downstairs are plasterboard, check under the floor upstairs to see if there is any gap where the plasterboard wall and downstairs ceiling meets the structural (brick or block) wall behind. Any gap there must be completely filled and sealed.

After that, to reduce the sound passing through you need high density materials, such as http://www.wickes.co.uk/heavy-density-insulation-pk5/invt/161189/
which needs to be fitted tightly between the joists with no gaps anywhere.

When fitting the new chipboard floor, glue all of the edges together and fill the gap between the floor and wall with mastic.

There is more that can be done, but unfortunately not without replacing the ceiling downstairs.

 

[donlogan]

Instead of pulling up the floor boards bring the ceiling down its a lot easier to rewire and run central heating pipes, then fit sound proofing plasterboard,

http://www.soundservice.co.uk/acoustic_plasterboard.html[/QUOTE]



You reckon? I don't know if acoustic plasterboard alone will be as effective as filling the floor above with a dampening material and sticking a membrane between joist and chipboard floor?

Also, wouldn't a new ceiling (made of acoustic plasterboard and plastering and painting it) amount to more than the cost of the same amount of chipboard upstairs if i did the floor option?

And what about using Celotex? Is it expensive?

Cheers.

 

[donlogan]

Loft insulation won't do much. Polystyrene will be totally useless, and will damage any cables it is in contact with.

The first thing is to make sure there are no gaps or cracks in the ceiling as even a tiny hole will let a lot of sound through. Where cables pass through the ceiling for a light etc., the hole should be sealed with mastic.
If you have downlighters, they will need appropriate covers sealing over them.

If the walls downstairs are plasterboard, check under the floor upstairs to see if there is any gap where the plasterboard wall and downstairs ceiling meets the structural (brick or block) wall behind. Any gap there must be completely filled and sealed.

After that, to reduce the sound passing through you need high density materials, such as http://www.wickes.co.uk/heavy-density-insulation-pk5/invt/161189/
which needs to be fitted tightly between the joists with no gaps anywhere.

When fitting the new chipboard floor, glue all of the edges together and fill the gap between the floor and wall with mastic.

There is more that can be done, but unfortunately not without replacing the ceiling downstairs.

Not necessarily disagreeing, but why would polystyrene sheet between joists, sealed at edges be totally useless? Surely polystyrene muffles sound well?

And i know that cavity wall type polystyrene balls damage cables, but solid sheet as well?

Brick walls downstairs, so no stud work.

What do you reckon to using a heavy density insulation in between joists upstairs (with decent carpet and underlay on chipboard floor) and then overboarding the existing ceiling downstairs with something like this:

http://www.noisestopsystems.co.uk/ceiling-soundproofing/nssc2-ceiling-board-30mm


Looks like there are a lot of options, so i'm open to opinions.

Thanks for the help.

 

[JohnD]

pull up the old chipboard, good,

put down new chipboard, bad

Put down 18mm ply instead. It is far better. Fix it tightly down with countersunk screws (drill pilot holes). Retighten the screws after a couple of weeks.

you can pack dense mineral wool batts between the pipes, they are heavy so they muffle noise better than light loft insulation. Increased wight mufles sound better. Leave no gaps, especially round the edges at the final joist.

Electrical cables should not be surrounded with insulation, it can go underneath.

Look out for and fill any gaps or pipe-holes round or through the flooring or ceiling with sand and cement or expanding foam. If somebody has cut holes in the ceiling to poke lamps through, you can make plasterboard boxes to go round the lamps.

 

[flameport]

Expanded polystyrene is mostly air (something like 98% of it), which is why it's very good for heat insulation.
Unfortunately, air is no use at blocking sound. Effective sound blocking materials are high density, such as the fibre insulation, rubber sheet, etc.

Polystyrene balls and polystyrene slab insulation are made of the same material, as are polystyrene cups, packaging, bean bag filler etc. They all damage PVC cables.
Celotex and other PIR insulation does not damage cable, however as they are also mostly air, they are just as unsuitable for sound insulation.

Overboarding the ceiling will help, although for best results resilient bars should be used to separate the existing and new ceilings.
Using these between two floors in a normal house is overkill, unless there are very specific reasons for wanting them (room being used for sound recording, dedicated to a home cinema etc.). Consideration must also be given to the amount of weight being added to the ceiling.

Also best to avoid websites dedicated to selling sound reduction items, as most of the materials can be obtained from normal building suppliers for considerably less.

 

[pred]

http://www.british-gypsum.com/produ...ssories/gyproc_acoustic/gyproc_soundbloc.aspx


Click on the literature PDF. I have phoned Lafarge a few times and found them quite helpful, http://www.lafarge.co.uk/wps/portal/uk/4-Plasterboard

I can board it out and skim it for a modest £1000 unfortunatly travel cost to Bournmouth £9000

 

[donlogan]

Ok cheers for that.

The house in question has 3 bedrooms upstairs, all average size. I'm not sure of the exact size of the unpstairs in square metres and i'm not sure of the cost of dense fibre batss etc, but does it sound like £500 would get enough materials to make a noticeable difference to a house of that size?

I think i'll probably go for dense fibre batts in between joists, some kind of membrane or something else applied to the top of the joists and decent underlay.

If that doesn't suffice then i'll think about overboarding the existing ceiling with resilient bars and acoustic plasterboardat a later date.

 

[joe-90]

Why bother - just tell the kids to shut up - it's your house isn't it?

 

[donlogan]

Why bother - just tell the kids to shut up - it's your house isn't it?

Ha, it's more likely to be me and mates with music/Tv/Xbox and general insults towards each other whilst my wife and newborn baby sleep in the bedroom above...

 

[donlogan]

Hi, can anyone recommend some suppliers of dense fibre matting acoustic mineral wool to put between joists in my floor?

The rewiring is almost done now and i will soon be putting a new chipboard floor down, so want to stick something in between joists to deaden the sound. There is nothing there at the moment, just plasterboard celing and chipboard flooring, so that looks like the reason that the sound insulation is so poor at the moment.

I need enough to cover around 50 square metres. I am hoping that this solution, plus some acoustic underlay will make a difference as i cannot afford to do any more. the cost of acoustic chipboard is more than 4 times the price of normal 18mm chipboard.

Is there a membrane that i can cover the joists in before putting down the chipboard?


If anyone has any links on where to find this stuff for a decent price, then it would be much appreciated.

Thanks.