Scale-height radial profiles for migrators, non-migrators and all stars in the time intervals 0.5 < t < 1.5 Gyr (top) and 1.5 < t < 3 Gyr (bottom). The green solid curves indicate the fraction of migrators as functions of radius during each time period. The scale-height for the non-migrating stars is approximately constant with radius for all models (blue dashed curves, top). Due to the inner disc cooling and outer disc heating in the vertical direction from migrators (dotted-red curve, see also Fig. 6), all discs flare (solid black curve).