Converted Attic Floor Sound Insulation

serox_21

Hi guys,

Over the weekend(and next week) I'm planning to change the floor boards on my converted attic.
I'm planning on replacing current chipboards with 18mm hardwood plywood (2440x1220) and I'm looking for advice on what rockwool type to use for sound proofing between floors.

Current attic floor(first floor ceiling) is made of

- 22/5cm joists(not equally distanced, average of 35cm)

- some fiberglass insulation(20cm) on 2 sides of the attic(there is around 1 m of storage space on 2 sides of the attic). No insulation for rest of the floor.

- 18mm chipboards(that squeaks on each step. This is the main reason I'm replacing the floor)

- 5mm carpet underlay

- carpet

Rockwool(around 30m2) options:

1. 150mm rockwool roll(4.38m2/roll, 22Kg/m3) - 38Euro roll
2. 100mm rockwool flexi slabs(4.32m2/pack, 38Kg/m3 ) - 49 Euro pack
3. 100mm rockwoll RW3 slabs(12packs, 60kg/m3) -408Euro (to be imported from UK. Prices in Ireland are to high)

Questions:

Would the first option work OK for sound insulation(persons talking in attic space, not to be heard on first floor). Not looking for impact noise.

Would it be a big difference in noise level reduction between this 3 options?

What else can be done in improving transmitted noise within moderate budget.

Planned budget is not to exceed 800- 1000 euro to replace floor boards and sound insulation.

5T3PH3N

How are you planning to prevent the edges of the plywood squeaking against each other?
And how are you gonna get full sheets up there?
Tongue and groove Osb is usually good for attic floors and it comes in 2.4x600mm sheets.
There is a foam tape you can get that sticks to the top of the joists and then you put your subfloor material down on that, acoustic joist tape or something like that, I'm not sure of the actual name of it.

For your insulation give Uvalue a call and see how much they are, I can't see how importing a bulky load is cheaper than buying from the main suppliers.

dodzy

2-3mm insulation under carpet....

Replace with 10mm foam underlay. Much better feel under foot and will definitely help with sound transmission and squeaky boards.

serox_21

5T3PH3N wrote: »

How are you planning to prevent the edges of the plywood squeaking against each other?
And how are you gonna get full sheets up there?
Tongue and groove Osb is usually good for attic floors and it comes in 2.4x600mm sheets.
There is a foam tape you can get that sticks to the top of the joists and then you put your subfloor material down on that, acoustic joist tape or something like that, I'm not sure of the actual name of it.

For your insulation give Uvalue a call and see how much they are, I can't see how importing a bulky load is cheaper than buying from the main suppliers.

Curent chipboards are t&g and squeaks at each step.
There are stairs and a normal door to the attic. I'ts coverted to a room. Full sheets will fit if door removed to have them in at an angle.

Maybe glueing edges together or cutting sheets so each edge is screwed on a joist.

408 euro price includes delivery to my door. 340euro is the price without delivery. At build4less one pack of rw3 is 56euro. So it's at least 160 difference. but I'll have to wait up to 2 weeks for delivery.

serox_21

dodzy wrote: »

2-3mm insulation under carpet....

Replace with 10mm foam underlay. Much better feel under foot and will definitely help with sound transmission and squeaky boards.

I think it's actually around 5 mm or more. It's a blue underlay.
In the future the plan is to have floor boards(laminated ) so proper underlay will be installed? Now squeaky floor is heard on the rooms bellow and fitting a new underlay won't help.

serox_21

After ringing around I bought 100mm Rockwool RW3(42.73 euro a pack) from UValue.

Thanks @5T3PH3N for suggestion.
Now all I have to do is install it over the long weekend(Sat and Mon).

serox_21

Replacing the sub-floor and repainting the attic room is now complete(1 week ago).

Materials for this project adds up to around 1000Euro.

- rockwool(9 packs) -380 euro
- OSB3 plywood(9 sheets 2.4x1.2) - 240 euro(includes delivery)
- acoustic impact strips(on top of the joists) -110euro
- screws and expanding foam - around 100euro
- paint(including brush and roller) - around 100euro

Renovation project took around 4 weeks since started. Usually I was working 1-2 hours during the week (1-3 days/week time) and 4 hours on Saturdays(3 day)