In construction, what do building codes typically require for foundation walls that retain earth and enclose floors below grade?

Building codes typically require damp-proofing for foundation walls that retain earth and enclose floors below grade. Damp-proofing is essential because it helps to prevent moisture infiltration into the foundation walls from the surrounding soil. This is particularly important in areas where the ground can become saturated with water, as excess moisture can lead to various issues, including mold growth, structural damage, and a decrease in air quality within the building.

While waterproofing is a more robust solution that can prevent water penetration even in severe conditions, damp-proofing is generally sufficient to handle the moisture levels typically present in soil around foundation walls. Building codes recognize this distinction and often require damp-proofing as a baseline to ensure that the foundation remains dry under normal conditions.

In contrast, options like ventilation and insulation, although important for overall building health and energy efficiency, do not address the primary concern of moisture control in the context of foundations. Ventilation may help reduce humidity indoors, and insulation can prevent heat loss, but neither specifically targets the moisture that can accumulate around foundation walls.