A vane arc segment includes an airfoil piece that defines first and second platforms and an airfoil section that extends between the first and second platforms. The first platform defines a gaspath side, a non-gaspath side, and a first platform radial flange that projects from the non-gaspath side. Support hardware supports the airfoil piece via the first platform radial flange. A thermal insulation element is situated adjacent the first platform radial flange. The support hardware supports the airfoil piece through the thermal insulation element.