In order to reproduce the peculiar magnetic field morphology of Saturn and the ice giants (Uranus and Neptune), dynamo modellers had to introduce a stably stratified layer somewhere in their modelled planet’s interior. The physical reasons for these stable layers’ existence have been qualitatively given, and linked to processes such as sedimentation of helium (Saturn) and an exotic phase of water (Uranus and Neptune). In this talk, I will first introduce both the reasoning behind including these stable layers in dynamo models, and the physical justification for their possible existence. Then, I will present the methods and results of a quantitative study on the feasibility of these stable layers using 1-D interior structure models.