Abstract: Disclosed is a refractory/heat insulating panel used in buildings and structures which must have a refractory performance. In the refractory/heat insulating panel (801), the mechanical strength and the fireproofing performance at the joint portions, which are weak portions in the panel, are increased by integrally forming inorganic boards (831) in the male and female joint portions (832, 836), filling a light-weight aggregate in the core material located at the male and female joint portions at a high density, or making the density of the core material at the joint portions higher than that at the center of the panel.

Abstract: A sandwich panel which is formed by sandwiching a core member of synthetic resin foam (plastic foam) between a front surface member and a back surface member into an unified body, is provided with plural gas-permeable members in the core member or/and at the boundary between the core member and the front and/or back surface member of the sandwich panel, whereby internal gas produced in the core member is discharged through the gas-permeable members to the outside of the sandwich panel.