Abstract: The invention relates to an insulation assembly designed for thermal protection of a structure, including three stacked layer of different types. The outer surface layer consists of a composite material with a mineral matrix, in particular made of clays capable of reacting in an aqueous medium, coating structural reinforcement fillers consisting of fibers, in particular as fabric, fiber layup, prepreg, mat, etc. The intermediate layer consists of a refractory mineral material such as a lightweight felt. The inner surface layer consists of a thermally insulating honeycomb material, in particular with a thermoplastic or thermosetting resin base. In addition, reflectors consisting of aluminized screen, can be provided at the interface of each layer.