Abstract: A heat and sound insulating panel assembly for wall, ceiling or floor construction consists of a plurality of interlocking vacuum-chambered panel elements fabricated from a relatively hard, low thermally-conductive, fire-resistant or fireproof material with heat-reflective, moisture-restraining coatings on its inner and outer surfaces. Abutting surfaces may be provided with sound-cushioning pads, and vacuum-chambered spacer column elements may be employed, interlocked between panel elements, for uniform increased panel wall thickness.