Excess moisture in foundation walls is generally caused by one of three things:
- Surface water infiltration
- Groundwater infiltration or
- A broken exterior pipe.
Generally the culprit is #1, surface water infiltration. In most cases, the water is coming from a gutter downspout dumping water right next to the foundation, or the ground surface is graded toward the house instead of away (negative drainage).
The problem is often misdiagnosed. Very often we are asked by homeowners to inspect their basement or crawl space after a "waterproofing contractor" has provided them a quote for installation of an interior perimeter drainage system (sometimes referred to as a "french drain"). That would be the solution for problem #2 - a rising groundwater table, but does not solve problem #1.
If the problem is indeed water coming from the gutter downspout or negative drainage conditions, you need to regrade for positive drainage and extend the downspouts away from the foundation.