Thermal insulation system intended to cover a wall of a building, comprising: - insulating panels each being in the form of a plate with corners, each of the panels comprising a porous compression-resistant material and a gastight barrier envelope for maintaining an internal vacuum that encloses the porous material, the panels being distributed in at least one layer of panels with rows of panels; - an external facing; - a framework for fixing the panels in said layer, so that said layer has a so-called front face on the same side as the external facing and a so-called rear face opposite to the front face; the framework comprising: rigid structural means (4, 5') arranged between the external face and said front face and suitable for bearing on at least one substrate of the building; - bracing devices that are, all or partly, supported by the structural means (4, 5'), and each comprising a support element arranged at a first axial end of the bracing device and intended to be fixed directly or indirectly to the wall; characterised in that the bracing devices form intermediate supports for holding the layer of panels and suitable for maintaining a separation between the external facing and said front face, the bracing devices, which are preferably non-metallic, each comprising: - a star-shaped element comprising a central portion that defines a longitudinal axis of the bracing device and branches (33a, 33b, 33c, 33d) suitable for coming into contact with edges of adjacent panels in the layer, the branches of the star-shaped element extending radially around the central portion; and - means (27, 37) for holding corners of the panels distributed on either side of the branches (33a, 33b, 33c, 33d) of the star-shaped element. - insulating panels each being in the form of a plate with corners, each of the panels comprising a porous compression-resistant material and a gastight barrier envelope for maintaining an internal vacuum that encloses the porous material, the panels being distributed in at least one layer of panels with rows of panels; - an external facing; - a framework for fixing the panels in said layer, so that said layer has a so-called front face on the same side as the external facing and a so-called rear face opposite to the front face; the framework comprising: rigid structural means (4, 5') arranged between the external face and said front face and suitable for bearing on at least one substrate of the building; - bracing devices that are, all or partly, supported by the structural means (4, 5'), and each comprising a support element arranged at a first axial end of the bracing device and intended to be fixed directly or indirectly to the wall; the framework comprising: rigid structural means (4, 5') arranged between the external face and said front face and suitable for bearing on at least one substrate of the building; - bracing devices that are, all or partly, supported by the structural means (4, 5'), and each comprising a support element arranged at a first axial end of the bracing device and intended to be fixed directly or indirectly to the wall; - bracing devices that are, all or partly, supported by the structural means (4, 5'), and each comprising a support element arranged at a first axial end of the bracing device and intended to be fixed directly or indirectly to the wall; - a star-shaped element comprising a central portion that defines a longitudinal axis of the bracing device and branches (33a, 33b, 33c, 33d) suitable for coming into contact with edges of adjacent panels in the layer, the branches of the star-shaped element extending radially around the central portion; and - means (27, 37) for holding corners of the panels distributed on either side of the branches (33a, 33b, 33c, 33d) of the star-shaped element.