Figure 4-10. Post-Tensioned Slab-on-Grade with Exterior and Slab Insulation
Figure 4-10 shows an exterior insulation for a post-tensioned slab. The vapor retarder runs continuously around the footing. The lower piece of rigid insulation is placed in the footing form, and the vapor retarder is sealed to it. After the footing is poured, the footing can be partially backfilled. Then the post-tensioning tendons are placed under tension. The upper piece of foam can then be applied and covered with a protective material. See Lstiburek (2006) for more information on this application. Additional foam may be used on the inside vertical face of the stemwall.