Usually in this scenario the main point of focus is the dividing floors between the dwellings and that is the point we need to apply soundproofing.
Insulation between floors in flats.
Children shouting loud music or even a noisy washing machine can create disturbances to the rest of the household.
This will also increase thermal insulation for the room above and below making them more comfortable to be in and quieter too.
Sound insulation between two levels.
Acoustic insulation is very effective at reducing airborne noise.
But more importantly spray foam insulation will provide great thermal efficiency.
Some older properties have airbricks between floors to help the floorboards breathe.
Acoustic insulation in the mid floor.
That means cold air entering the property and bypassing your wall or loft insulation in these cases it is really worth considering insulation which will allow the air to circulate but prevent it from getting into the living area.
Hard floor coverings without an isolation material between them and floor boards.
This makes soundproofing a flat a far easier job to undertake.
Alternatively battens can be secured to the underside of the joists and gmw fitted between these in much the same way as between the main roof joists.
We mentioned earlier that one of the reasons you need to insulate between floors is make them more soundproof.
Given our fondness for timber frame and lightweight block walls for thermal insulation the inner leaf of a cavity wall is an easy route for flanking transmission to bypass a sound resistant wall or floor.
If your second floor is above a cold and unheated area like the garage for example spray foam will take care of those cold floors that are.
The result is noise transmission between walls and often floors.
To achieve real soundproofing between two rooms the walls need to be mass loaded and isolated from one another.
Commonly in this scenario the floors are standard timber joists with floor boards laid on top no insulation between joists and a standard 12 5mm plasterboard on the ceiling below.
Putting insulation between the ground and first floor should in theory stop sound vibration and heat from moving between levels in your property.
The soft material will help to absorb sound travelling through the floor.
Carpeted flats or apartments will already benefit from the natural insulation the material provides with wool and pile carpets offering particularly good levels of sound protection.
Unfortunately stud partition walls usually only include a small amount of thermal insulation and isolation or decoupling is certainly not taken into consideration.
The main reason to insulate between floors is to reduce the noise transfer between floors.
The underside of the rafters in this case will need to be finished with a suitable vapour control layer vcl and plasterboard to provide a suitable internal finish to the roof.