Build Dry From the Inside Out
Finishing over damp concrete guarantees long-term problems. Before framing, inspect foundation walls for cracks and efflorescence. Apply a cementitious waterproof coating or vapor-permeable membrane to block liquid water but allow vapor diffusion. Follow with dimple drainage mats that channel any seepage down to a perimeter drain or sump pump. These create a small, ventilated air gap behind framing so moisture never touches drywall or insulation.
Insulation & Framing
Install rigid foam panels (XPS or closed-cell spray foam) directly against concrete for thermal break and moisture control. Tape seams with compatible vapor tape. Frame non-load-bearing steel or pressure-treated wood studs in front, keeping at least a 1/2” gap between foam and framing for ventilation. Avoid fiberglass batts—they absorb moisture and support mold.
Electrical & Plumbing Routing
Keep wiring and pipes within stud cavities, not against concrete. Seal all penetrations with fire-rated foam or acoustic sealant. Install recessed boxes with vapor gaskets to maintain airtightness. At floor level, use treated sill plates with sill gasket membranes to prevent capillary wicking.
Humidity & Monitoring
Once walls are closed, maintain 45–50% RH with a ducted dehumidifier. Add moisture sensors behind access panels near sump or utility zones. Periodically inspect drainage mats through removable baseboards to ensure airflow and dryness.
For assembly diagrams and product recommendations, see NYC basement waterproofing & moisture control.