Porch flooding issue

[Nathan]

I have an enclosed porch, built on a preexisting concrete patio slab.

Whenever there is heavy or prolonged rain, the slab becomes very damp, especially at the two corners farthest from the house.

The problem is not gutter overflow, as the gutters and downspouts are clean and discharge water several feet away, and downhill, from the slab.

I have removed earth from the slab for about a foot back from the worst corner, but there is still water intrusion.

[home improvement guy]

Knowing the age of the house and when the problem started would be helpful for a solution.

Ground shifts, and trees and shrubbery planted as babies grow into adults and change the way moisture affects structures.

The slab and porch might not have been built to standards designed to prevent such intrusion in torrential and prolonged downpours.