Rockwool Sound muffling in floor

[mickael]

Hello. We are sound insulating underneath between ground floor ceiling and 1st floor subfloor. The distance between joists is at 360mm and the height between the plasterboard downstair and the subfloor is at 75mm. Can we use 100 x 400 rockwool slab? We have started. Please see example below

 

[JohnD]

What sort of carpet and underlay will you be fitting?

Is the ceiling below new? How thick is it?

Have you sealed all holes in the ceiling, e.g. for pipes and cables, and round the edges of the room? There aren't any downlighter holes, are there?

What sort of noise do you want to block?

 

[mickael]

Hi John. Thank you gor the quick reply. we have just re boarded the ceiling between the joist on the ground floor. We are now replacing the subfloor because it was in very poor condition. We want to insulate for sound because we can here everything happening downstair from upstair and vice versa. There is not much space between the plaster board on the ceiling and the subfloor on the 1st floor. Only approx. 75mm. and the distance between joists is at around 370mm. I have started with 100x400 rockwool slab and it fits quite tightly. Do you think that's okay or is that going to press to much on the ceiling board downstair?

Thplaster board thickness is at 9.5mm

The subfloor will be 22mm wisa sprucefloor plywood tongue and grooved.

we will not have carpet. We were considering engineering wood floor on top of the subfloor with a layer of cork in between.

We haven't sealed any holes.


Thanks
Mickael

 

[StephenStephen]

How to sound insulate upstairs wooden floor

Hi all, We've an upstairs wooden floor which we want to reduce noise coming down to the room below. We want to reduce both the sound of footsteps and the sound of speech Currently there are spotlights in the ceiling below, so we're going to remove those and fill the holes in the plaster...

www.diynot.com

We found the rock wool bats work well, but do have an air gap between the top of the bats and the underside of the floorboards.

 

[JohnD]

Seal the holes. Noise comes through gaps. You can use firefoam or caulk. Even if you are not obliged to use the fire grade I think it is a wise precaution.

An uncarpeted floor will be needlessly noisy. Speech will travel through it. Footsteps, and especially chairs or furniture moving, will be very annoying.

A double layer of plasterboard, plus skim, will be better than your thin layer.

 

[JohnD]

We found the rock wool bats work well, but do have an air gap between the top of the bats and the underside of the floorboards.

I don't think the gap is neccessary, because the batts will not resonate or transmit impacts.

 

[big-all]

my thoughts
insulation between floor and ceilings will have little effect on sound transmission unless its heavy to deaden resonance you have a solid floor connected to solid timber connected to solid plasterboard so the vibration is travelling easily yes the filling voids will help but wont stop the vibrations unless the they have enough weight to dampen the vibrations to stop it being a sounding board

 

[JohnD]

my thoughts
insulation between floor and ceilings will have little effect on sound transmission unless its heavy to deaden resonance you have a solid floor connected to solid timber connected to solid plasterboard so the vibration is travelling easily yes the filling voids will help but wont stop the vibrations unless the they have enough weight to dampen the vibrations to stop it being a sounding board

I find it muffles airborne noise (speech, TV, radio, music)

But would not expect to make so much difference to impact noise (hammering, drilling, walking on uncarpeted floor, skittles) apart from the airborne element of it

 

[big-all]

I find it muffles airborne noise (speech, TV, radio, music)

But would not expect to make so much difference to impact noise (hammering, drilling, walking on uncarpeted floor, skittles) apart from the airborne element of it

i helped my neighbour build a wooden garden room that he used 3"rockwool for heat and sound deadening
i walked past 6foot away from the back through next doors garden and he could cleary hear my normal conversation so was very disappointed as he was hoping to practice rock solos on his drum kit