Abstract: An insulation module fabricated from ceramic fiber blanket material. The module includes a horizontal base of blanket material and body portion of blanket material secured to the top thereof. The body may be blanket material in a zigzag or Z-configuration with free ends seated against the base or a series of U-folds with the bight portions thereof being remote and directed from the base. Alternatively, the body can be blanket material wound into helix of an overall rectangular cross section and having its free edge seated against the base. The base can be formed of superposed blankets that are staggered or offset so as to make rabbet-like joints with corresponding parts of adjacent modules. The modules, which are generally of rectangular configuration, are provided with protective covers that protect them, retain them in a prestressed (laterally compressed trapezoidal) condition, and which facilitate installation.