What must be the compressive strength of concrete for basement slabs that are subject to rain?

The compressive strength of concrete for basement slabs that are subject to rain should be at least 2,500 PSI. This strength ensures that the concrete can withstand the loads it will be subjected to, including both the weight of the slab itself and any potential hydrostatic pressure exerted by water accumulation during rain events.

Concrete with a compressive strength of 2,500 PSI is sufficient for residential applications, providing a balance between strength and cost-effectiveness. Higher strength concrete, while beneficial in some scenarios, is not necessary for typical basement slab applications unless there are specific engineering requirements or local building codes that dictate otherwise.

This selection is based on common practices and standards within the industry for durability and structural integrity in moisture-prone environments such as basements.