Acoustic insulation is likely to be required when converting an upper floor commercial floor to a residential flat if the ground floor is used for commercial premises.
Likewise if a property will, following renovation, accommodate more than six unrelated tenants (sui generis).
The equipment used and the certification required by acoustic engineers is expensive.
Preventing sound transmission is complex as it involves air born and vibration sounds though connecting timber joists and staggered wall studs.
Special ‘acoustic hangers’ help to absorb sound and minimise transmission. Suspended ceilings create an air cavity between surfaces; ideally the two separating surfaces should have minimal contact if possible using isolation washers and sound barrier pads.
Any perimeter holes, gaps or joints should be filled with inter-acoustic sealant.
Skirting boards may need to be removed to allow floor insulation to continue to the wall with skirting replaced above any new floor.
The process is likely to involve 1 hour fire separation barriers too, where intumescent collars and intumastic sealant is likely to be required. Service and drainage pipes and cables passing through surfaces also allow transfer of sound, smoke and flames.