A lightweight base coat composition is provided that comprises a resin dispersion such as acrylic latex/binder, lightweight aggregate and optionally cementitious material to form a lightweight base coat composition. The reduction in weight is achieved by the replacement of fine sand aggregate with lightweight aggregate, which also provides additional insulation values. The improved insulation value allows darker colored finish compositions to be applied over the base coat without the risk of damaging (melting) the expanded polystyrene insulation (EPS) foam.