Under Floor-Board insulation, for noisy neighbours in lower flat

phillyt

Standard Member
Does anyone have any suggestions or advice on how to insulate against noisy neighbours under you?

Floor boards are accessible with joists underneath (and a few pipes for water/electrical wire containers)... could I spray some expanding foam under the floor boards to absorb some of the noise?

Any other suggestions for fixes or materials to stuff down there appreciated and welcome :)

EDIT: Its primarily loud TV volume and voices
 

ufo550

Well-known Member
I would seek some guidance, from the many companies that carry out this sort of work.

You should also consider what you might do, by covering electrical wiring completely in insulation. If your a tenant or leasehold, you also might need to get permission to do any such work.
 

noiseboy72

Distinguished Member
I would be very dubious about using anything as permanent and hard to remove as expanding foam. If a pipe or cable needed access, you've made life a lot harder for yourself.

Other than adding mineral fire retardant insulation into the void, you might be better to concentrate on what you can do above the floor boards. Thick underlay, green glued boarding and a thick carpet will probably all help significantly.
 

drummerjohn

Well-known Member
You cannot use standard expanding foam as it is not fire retardent. It's also not good at absorbing sound.

Whatever you put in there must have the ability to stay suspended in case of fire below it destroying the ceiling and allowing burning hot embers to rain down.

Rockwool, or similar, is best for sound but you need to put in wire wesh (chicken wire) to stop the material falling below in case of fire.
 

IronGiant

Moderator
I've never seen chicken wire installed under loft insulation, so why is it needed here?
 

drummerjohn

Well-known Member
A fire will destroy the ceiling giving way to a lot of extremely hot insulation which will reign down on anyone trying to escape. It's used for loft conversions primarily but makes sense if you're pulling up floorboards.

All new cables that cross probable exit routes should also be clipped using metal clips so they do not drop down and cause obstruction.

Do not use standard expanding foam as overtime it destroys the PVC sheath of the cable.


I've never seen chicken wire installed under loft insulation, so why is it needed here?
 
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ufo550

Well-known Member
A fire will destroy the ceiling giving way to a lot of extremely hot insulation which will reign down on anyone trying to escape. It's used for loft conversions primarily but makes sense if you're pulling up floorboards.

All new cables that cross probable exit routes should also be clipped using metal clips so they do not drop down and cause obstruction.

Do not use standard expanding foam as overtime it destroys the PVC sheath of the cable.

Not that I'm suggesting the use expanding foam in this instance, but there are fire retardant expanding foams, and most have no effect on the sheathing of cables (one would need to verify with manufactures instructions), It could however, affect their current carry capacity, and might need derating.

Ceilings formed by plasterboard, are fire rated, and dependant on their rating and are designed to to protect structural parts and services. Most if not all typically sourced insulation is also naturally fire retardant. So the plasterboard, would delay any nasty itching insulation falling on anyone's head, for a specific period of time, during a fire.

Only electrical cables (etc) that are not protected by said plasterboard ceilings, require metal fixings. But that applies to all areas now not just escape routes.

Deleted.
 
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drummerjohn

Well-known Member
Not that I'm suggesting the use expanding foam in this instance, but there are fire retardant expanding foams, and most have no effect on the sheathing of cables (one would need to verify with manufactures instructions), It could however, affect their current carry capacity, and might need derating.

Ceilings formed by plasterboard, are fire rated, and dependant on their rating and are designed to to protect structural parts and services. Most if not all typically sourced insulation is also naturally fire retardant. So the plasterboard, would delay any nasty itching insulation falling on anyone's head, for a specific period of time, during a fire.

Only electrical cables (etc) that are not protected by said plasterboard ceilings, require metal fixings. But that applies to all areas now not just escape routes.

Deleted.

Belt and braces for me.
 

AMc

Distinguished Member
Every day is a school day - I would have expected chicken wire to give up almost immediately under fire but seems I was wrong.


As above expanding foam will be fairly ineffective. If you could totally seal the floor from the room below then you'd have some impact but a solid connection between their ceiling and your floor might make it worse through conduction.
Rockwool should be a lot easier and cheaper if you're going to lift the floorboards.
 

reevesy

Distinguished Member
Thinking back to when I did some walls....and after a lot of research..

Loads of stuff out there in Google land about this ...but my 2 pence is acoustic insulation..local building merchants have it stock ... similar to loft insulation but a lot more denser ..easiest way to cut it is with an old bread knife. Tightly fit between joists

My experience with sound insulation is it all works better with a combination of things ..you can get acoustic rubber ..mats or sheets ..I got some 2 or 3 mm thick stuff from Amazon ...think of sound as water ..it's all about stopping the leaks ..

Not sure about your joists but if you can stuff loads of acoustic insulation down..then rubber over the top ..then boards back down?

People do say that 'green glue' will do the same thing as the rubber..it's pricy ..but might be better to use before putting boards back down..not sure how good it is for floors but experts use it a lot on walls

If you can I'd put extra rubber down first ..then insulation..then rubber again?

I did 2 Walls...one had the rubber as well as insulation and acoustic plasterboard ..the other same but no rubber.
....rubber wall Was a lot better .

Anyway ...all a pain in the derrier so hope it goes well

I cured the noise problem in the end.........sold the house !
 
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