This research presents preliminary results of the development of a lightweight, sustainable and fire-safe structural insulating panel by combining very lightweight aggregate concrete (VLWC) as a core and textile-reinforced cementitious composite (TRC) as skins. The potential disadvantage of this system using TRC compared to steel reinforced concrete may be its behaviour under fire. A VLWC, with expanded clay aggregates, was developed focusing on density and high temperature stability. This study investigates the behaviour of each of the constituent materials, TRC and VLWC and then of their combination in the sandwich structure at ambient temperature and cooled-down after being submitted to elevated temperature. The residual mechanical behavior of VLWC after heating up to 600 ℃ has proven to be as satisfactory as traditional concrete, if not better, particularly regarding tensile strength. The effect of high temperatures up to 600 ℃ on the tensile behaviour of TRC with coated-AR glass fibers was investigated. The first cracking stress and the ultimate tensile strength decrease with the temperature from 150 ℃. But the originally three-staged response (in ambient conditions) is maintained up to 300 ℃, and the ultimate strength is still significantly improved compared to the first cracking stress value. For the sandwich panels, no delamination from the skins appears. At ambient temperature, a similar three-stage behaviour is observed with satisfactory mechanical behaviour. Up to 300 ℃, the residual behaviour is similar, with a limited decrease in maximum loading. Yet, at this temperature, a few specimens undergone delamination during the heating phase.