The end user of a project may wish for some specific acoustic target to be reached. For example, there might be a specific requirement on the sound insulation of the fagade, for example, 5 dB or more over the value required by the regulations. There might also be a requirement on the noise of mechanical services or on the impact sound reduction. Last but not least, the end user may wish for a specific room to be thoroughly insulated in order to turn it into a studio or a rehearsal room.
It is not unusual for a landlord to issue a set of rules regarding the expected behavior of tenants. Among a variety of petty requirements (e.g., bicycles shall not be left by the entrance), there often are items regarding what is considered noisy behavior to be prevented (e.g., talking loudly in the public spaces of the building, listening to loud music, and being agitated after normal hours), as defined in the rules.
There also are some rules regarding the eventual work that is allowed inside a dwelling. For example, there often is a contractual requirement forbidding the owner or tenant to replace the floor covering by a material of his own choice due to the possible consequences regarding the transmission of impact sound in the building.
All the regulations above apply to new construction. What about rehabilitation projects? Well of course it usually is hard to achieve acoustic performances similar to those of a modern building in a structure that is more than 50 years old.
The usual basic target is to try to avoid degrading the acoustic performance of the existing building. This means that an acoustic diagnosis will have to be performed prior to any design work to find what those performances actually are. This will be a contractual reference point, as well as a basis for the design of the rehabilitation project.