Wet basement questions are among the most common here – here’s a consolidated guide for 2026.
First: diagnose the source
- Lateral pressure (saturated soil against wall) → exterior waterproofing addresses root cause
- Hydrostatic pressure (water coming up from below) → interior drainage systems capture and redirect
- Crack infiltration → targeted injection appropriate for isolated cracks
Interior waterproofing (drain tile systems):
Perimeter channel cut at footing, drainage pipe installed, covered with concrete. Water captured and directed to sump. Brands: WaterGuard, B-Dry, SuperSump.
- Cost: $80-$140/linear foot installed
- Full perimeter (1,000 sq ft basement): $12,000-$22,000 including sump pump
Exterior waterproofing:
Full excavation to footing, membrane application, new drainage board and weeping tile, free-draining backfill. Addresses problem at source.
- Cost: $200-$400/linear foot of wall
- Full exterior on semi-detached: $35,000-$70,000
Targeted interventions:
- Crack injection (epoxy/polyurethane): $400-$800 per crack
- Window well drain: $500-$1,500 per well
Sump pump: Don’t skip battery backup. Primary + battery backup + alarm: $1,200-$2,000 installed. Pump failure during storms is the leading cause of catastrophic basement flooding in Ontario.
Waterproofing contractor referrals at home.renovation.reviews