Even with commercially available materials, sourcing for a high-performance home can be difficult, since those materials may not be lying around a local supply yard. It was determined that a 3-inch-thick polyiso board would work best for inside the formwork of the foundation walls, and the supplier confirmed it was available. However, when it came time for the foundation walls, the supplier said the board would first have to be manufactured, potentially resulting in a month’s delay. After waiting two weeks, the project team opted for an alternate solution — using readily available 2-inch-think polyiso board and applying a separate layer of polyiso to the inside of the foundation wall after the forms were stripped. The change in thickness of foam inside the formwork (from 3 to 2 inches) meant ordering new break-back form ties, delaying the project by an additional week.
All told, the material availability and sourcing issues, coupled with weather delays, increased the cycle time for the foundation by about one month.