Protect From the Outside In—and the Inside Out
Long-term waterproofing begins before finishes. Start with an exterior drainage system whenever possible—footing drains wrapped in filter fabric, a gravel trench, and waterproof foundation coating. Where excavation isn’t feasible, interior retrofits combine vapor barriers, drainage mats, and sump systems to redirect water safely.
Key Layers of Protection
1) Apply a crystalline waterproof coating or elastomeric membrane on interior masonry walls.
2) Install a dimple drainage mat to channel seepage to the perimeter drain.
3) Connect drains to a sealed sump pump system with high-water alarm and battery backup.
4) Add a continuous vapor barrier under flooring and behind wall insulation to block humidity migration.
Moisture Control Integration
Combine waterproofing with ducted dehumidifiers maintaining 45–50% RH and energy recovery ventilation for fresh air. Use inorganic finishes—metal studs, closed-cell foam, cement board—to prevent future mold growth even if minor moisture occurs.
Testing and Maintenance
Before finishing, perform a 24-hour water test and infrared inspection to confirm dry surfaces. Service sump and dehumidifier filters quarterly, and maintain gutters and grading outdoors to keep runoff away from walls.
Get NYC-compliant waterproofing details and sump integration plans at NYC basement waterproofing & moisture control.