What Is Exterior Waterproofing?
Exterior waterproofing addresses water at its source, outside the foundation wall, before it can apply hydrostatic pressure or find a path through the wall. It is the most comprehensive waterproofing approach and is most appropriate for foundations with significant water infiltration, deteriorating original waterproofing membrane, or structural wall damage that requires exterior access for repair. The process involves excavating to the base of the foundation wall, cleaning the wall surface, applying a waterproofing membrane (sheet-applied or liquid-applied depending on wall condition), installing a drainage board to channel water downward, and placing a perforated French drain at the footing to carry water away from the structure. Exterior waterproofing is more disruptive than interior methods (landscaping and hardscape removal is required) and is typically more expensive, but it stops water at the outside face of the wall rather than managing water after it enters. APS recommends exterior waterproofing when interior drainage would be insufficient or when the exterior wall requires direct access for structural repair.
How APS Approaches Exterior Waterproofing
- 1
Free On-Site Assessment
A trained APS technician visits your property, documents the problem, and identifies the root cause before recommending any repair.
- 2
Written Estimate
You receive a clear scope of work and cost with no obligation. We explain the method chosen and why, in plain language.
- 3
Repair and Transferable Warranty
Our trained crews complete the repair using professional equipment. All APS repairs carry a warranty that transfers to future owners.
What Does Exterior Waterproofing Cost?
$8,000 to $25,000+ depending on wall length and site conditions
Frequently Asked Questions
When is exterior waterproofing the right choice?
Exterior waterproofing is most appropriate when interior drainage cannot address the water volume, when the foundation wall itself is deteriorating and needs membrane replacement, or when structural wall repair requires exterior excavation anyway.
How disruptive is exterior waterproofing?
Significant excavation is required alongside the foundation walls. Landscaping, shrubs, hardscape, and grade within several feet of the foundation will be disturbed. APS documents and restores the excavation area.