1. Photo Source: Summerhill	2. Photo Source: Summerhill
3. Photo Source: Summerhill	4. Photo Source: Summerhill

In some cases the stepped off wall in front of the concrete is extended all the way to the ceiling, creating an extra deep cavity in the upper portion of the wall. This cavity must be completely filled with insulation in order to avoid convection currents, which can significantly reduce the effective R-value of the wall. Code does not distinguish between pony wall and exterior wall, therefore it must be insulated to the same level as the exterior walls, but can also be insulated to a higher level than the exterior wall, due to the thicker concrete wall below.