Sound insulation between two rooms is not governed only by the sound insulation characteristics of the separating element. Other surfaces must be considered, such as:</p>
<p>any facade walls that run along the external walls of both rooms<br />floor <br />ceiling and <br />any internal connecting walls <br />ducting and pipe-work</p>
<p>These are called flanking paths. Transmission paths for a common room pair are shown below.