| Where To Insulate |
|
2B between the studs and rafters of exterior walls and roof; 2C ceilings with cold spaces above; 2D extend insulation into joist space to reduce air flows. 3B foundation walls above ground level; 3C foundation walls in heated basements, full wall either interior or exterior. 4B slab floors built directly on the ground;** 4C as an alternative to floor insulation, foundation walls of unvented crawl spaces; 4D extend insulation into joist space to reduce air flows. *Well-insulated attics, crawl spaces, storage areas, and other enclosed cavities should be ventilated to prevent excess moisture build-up. **For new construction, slab on grade insulation should be installed to the extent required by building codes, or greater. |
