A thermally insulating floor for lining a flooring wall, comprising: - a decorative coating layer, forming an upper layer of the floor; - insulating panels each having a plate shape, each of the panels comprising a compression-resistant porous material and a gas-tight barrier envelope, closed under vacuum, which contains the porous material, the panels being distributed in at least one thermal insulation layer spaced relative to the decorative layer, and preferably located between sound insulation means and the decorative layer; - at least one mechanical protective layer, which is insulating against moisture and arranged between the thermal insulation layer and the decorative layer, comprising a plurality of protection elements; - a framework for fixing and maintaining the panels under the decorative layer, so that said thermal insulation layer has an upper face on the side of the decorative layer and a lower face opposite the upper face, the framework comprising a plurality of rigid boxes structuring the thermal insulation layer, knowing that each box is provided with a bottom, a set of side walls and an upper opening delimited by an upper annular edge of the box; wherein the internal volume of the boxes contains at least one of the insulating panels; and wherein the decorative layer comprises rigid coating elements which each comprise a lower face facing, and preferably in contact with, one of the protection elements, the rigid coating elements further comprising interconnection members for connecting two adjacent coating elements edge to edge, characterised in that the thermally insulating floor further includes the sound insulation means which are distinct from the mechanical protective layer and in the shape of a layer formed of sound insulation elements, said internal volume being delimited by the set of side walls and filled by a multilayer assembly which does not extend beyond the upper edge, said multilayer assembly comprising: - one of the acoustic insulation elements on the bottom side of the box above the base plane of the box; - one of the mechanical protection elements, closer to the upper opening than the thermal insulation layer; - one of the insulating panels, at a distance from the upper opening and between said sound insulation element and said mechanical protection element. - a decorative coating layer, forming an upper layer of the floor; - insulating panels each having a plate shape, each of the panels comprising a compression-resistant porous material and a gas-tight barrier envelope, closed under vacuum, which contains the porous material, the panels being distributed in at least one thermal insulation layer spaced relative to the decorative layer, and preferably located between sound insulation means and the decorative layer; - at least one mechanical protective layer, which is insulating against moisture and arranged between the thermal insulation layer and the decorative layer, comprising a plurality of protection elements; - a framework for fixing and maintaining the panels under the decorative layer, so that said thermal insulation layer has an upper face on the side of the decorative layer and a lower face opposite the upper face, the framework comprising a plurality of rigid boxes structuring the thermal insulation layer, knowing that each box is provided with a bottom, a set of side walls and an upper opening delimited by an upper annular edge of the box; - one of the acoustic insulation elements on the bottom side of the box above the base plane of the box; - one of the mechanical protection elements, closer to the upper opening than the thermal insulation layer; - one of the insulating panels, at a distance from the upper opening and between said sound insulation element and said mechanical protection element.