1st floor insulation thickness

[motorbiking]

I have my 1st floor boards up and currently there is no sound insulation in there. I want to take advantage of the opportunity and was thinking of using 100mm loft role. Is this about the thickness used for sound insulation as per building control. I’m not required to be compliant but might as well follow the code.

 

[^woody^]

100mm Rockwool or equivalent, not just loft roll which may not have the sound insulation qualities

 

[motorbiking]

I was hoping you wouldn’t say that given the cost of rock wool vs the other brands.

 

[freddiemercurystwin]

Or 100mm knauf acoustic roll.

 

[motorbiking]

Am I wasting my time with this stuff. Knauf Earthwool Loft Roll 44?

 

[freddiemercurystwin]

The point in using sound insulation wool as opposed to heat insulation wool is that sound insulation wool is denser which improves the sound insulation so if you want to maximise sound insulation then use sound insulation designed for the job. Or don't bother and have less effective sound insulation.

 

[HERTS P&D]

I removed all my downstairs ceilings and filled with insulation, then double boarded.

The house is much warmer and there is no sound transfer from downstairs to upstairs.

Andy

 

[JohnD]

double boarded.

sound blocking is largely proportional to the weight and thickness of the barrier.

I had a thick lime plaster ceiling fall down, and realised how effective it had been.

I've used the lightweight loft rolls, which do make some difference

blocking all holes and gaps is important

there are tables of sound attenuation by product type and thickness somewhere.

 

[jeds]

There's a rule of thumb; 90% sound travels through 10% gaps. Seal all gaps/edges with acoustic sealant.
Also, high density materials attenuate low frequency sounds, whereas low density materials attenuate high frequency sounds. So you need a combination of layers of materials.