Can resilient bars be retrofitted?

[indus]

Hi

I recently had a loft conversion done and the level of impact noise we get below is unacceptable. I'm investigating solutions have been looking at www.soundstop.co.uk

At the moment there is no carpet up there, it's just plywood (which has been well screwed down)

As it's a loft conversion head height is at a premium.

Anyway, I'm looking at doing a combination of things including joist caps. On this diagram they also show resilient bars, can these be easily retrofitted or would it involve taking all the joists up?

http://www.soundstop.co.uk/solutions/floor_access/under_floor/floor_solution_2.php

Thanks

 

[tony1851]

Resilient bars are fitted from below on to the ceiling and do not require work to be done from above.
You can reduce impact sound penetration from above by installing decent underlay and carpet.

 

[indus]

Hi Tony

I cannot damage the ceilings of the rooms below so I assume resilient bars are out.

Underlay and carpet may well improve things but the impact noise is so bad that I don't want to take the risk of laying the carpet and then finding it is still really bad.

So I'd rather take some additional steps as well. Joist caps are relatively cheap and I presume easy to fit.

Soundstop also sell something called mute boards which are 18mm cement impregnated boards, but I have no idea whether they actually any better than 18mm tg chipboard

Thanks

 

[tony1851]

Did they put any sound-insulation batts between the joists when they were building the floor?

 

[indus]

Hi Tony,

I'm not sure what sound insulation battens are tbh. Here are a few pics of the floor.

 

[catlad]

Put some rockwool soundproof slabs between your joists, it looks like loft insulation but it is not on a roll, it comes in slabs and it is about three times as dense.

 

[tony1851]

The sound-insulation batts are mandatory in new domestic floors - they will probably be shown on the plans for your conversion.
The photos don't show any but that doesn't mean they won't have been installed later, perhaps when the ceiling was applied.
If this is up to standard (and your previous pics show what looks like a good conversion), there shouldn't be any real difference in sound insulation when compared with the existing floor structure between ground- and first floor.
I strongly suspect your problem is just lack of carpet and underlay upstairs.

 

[indus]

Catlad, thanks, I will be putting sound proofing rockwool down but I suspect it will help with airborne rather than impact sound.

Tony, I don't think any other battens were put down. What do these sound proofing battens look like? And what do you mean they would have been fitted when 'the ceiling was applied'?

Perhaps the new loft floor is actually no worse than existing but its impact in reality is. What I mean by this is that footfall in the first floor bedrooms won't wake up anybody on the ground floor. However footfall on the loft floor disturbs people trying to sleep on the first floor. So basically the loft floor needs to be better insulated than the existing floor

Thanks for your help

 

[tony1851]

Indus; you keep referring to 'battens', but they are, literally, 'batts'. They are just slabs of dense rockwool, about 4ft long and 16" wide, which are intended to go between the joists. They help to cut down airborne sound transmission. Impact sound transmission is best reduced by underlay/carpet or - at considerable extra cost and disruption- a floating floor. This is essentially a layer or layers of boarding on top of a special quilt. It would reduce headroom by at least 2".
Just try carpeting first!

 

[indus]

Sorry Tony, when you referred to 'batts' I thought you meant some kind of special.battens

I only have regular rock wool insulation between the joists at moment but that can.easily be changed for the acoustic/dense variety.

I will of course lay good quality underlay but what do you think about the acoustic joist caps and mute boards in the link?

Thanks

 

[catlad]

Those joist cushions should help not sure how much, you will have to let us know if you decide to use them.

 

[indus]

Thanks Catlad.

I presume fitting the joist caps is fairly easy? Just unscrew and take up all the chipboard, fit the joist caps and then refit the chipboard?

Also if you look at that link they sell something called 18mm muteboard. Do you think these are actually superior to normal 18mm chipboard or is it just marketing blurb?

Cheers

 

[chickenlips]

If your looking at fitting a resilient bar onto your joists, then have a look at these http://www.proctorgroup.com/products/acoustic-solutions/profloor-dynamic-batten
These are designed to reduce impact sound but the do add an extra 50-80mm to you floor.

Although I have to agree with tony1851, fitting a good underlay/carpet and sound insulatio batts will reduce impact sound greatly without the need for any other work.
Also when your flooring is fitted make sure its glued to the joists, with a D4 expandable glue. This will also help reduce the impact sound.

 

[indus]

Thanks CL

I will probably do as mentioned ie slabs of acoustic rockwoll and then a good quality underlay. All other things then add to the floor height ie the joist caps are 12mm.

The battens you have linked to are way too thick, as its a loft conversion I don't have the ceiling height to play with.