The cost-effective interventions: resilient layer floor build-ups, acoustic plasterboard on party walls, attention to service penetrations, and well-sealed door perimeters. Done together they get most properties to a comfortable acoustic standard.

Specialist acoustic floors and walls are available where the building or the tenancy mix demands it, but the standard interventions are enough for most domestic flat conversions.

Adding acoustic upgrades after handover is several times more expensive than building them in. Worth the conversation at design stage.