Another option for a transition detail at grade would be adjusting the formed and poured foundation wall to Logix ICF (Figure 3). Since Logix ICF walls incorporate continuous insulation on the interior and exterior of the wall assembly, additional sheets of foam board insulation typically aren’t required unless aiming for the Passive House Standard or building in Climate zones 7 or 8 in North America.
To ensure a thermal bridge is not present at the transition between the above and below grade wall assemblies, the above grade exterior insulation should be set flush with the exterior face of the Logix ICF foundation.
The joint between the two insulations can be sealed with caulking or tape and the Logix ICF foundation will require a layer of waterproofing – either a peel and stick or liquid applied membrane that extends down and over top of the footing.
Halo® Exterra® will still function as the water control layer for the above grade wall and an interior membrane will provide the air and vapor control layers. Since foam insulation is classified as a combustible material by building codes across North America, it must be covered with a thermal barrier.
However, a studded wall is not required for the interior of the Logix ICF foundation wall as the gypsum board can simply be fastened through the insulation back to the webs of the ICF or glued directly to the insulation.