There are no laws dictating that guaranteed building replacement is mandatory, but it does make things easier should something catastrophic happen that renders your home unliveable. However, if a catastrophic event were to severely damage your home, the last thing you want to worry about during the rebuilding process is if you have enough coverage to ensure your new home is rebuilt to the same quality and standards as the former. Also, guaranteed building replacement cost coverage takes into account changes in bylaws so any mandatory upgrades that are needed to comply with city standards are included.