Window wells for basement egress windows are required by Ontario Building Code for all below-grade bedrooms and are one of the most common sources of basement water infiltration when improperly installed.
OBC Egress Window Requirements
All basement bedrooms require egress windows compliant with OBC 9.7.2. Window well requirements:
- Minimum 550mm clear width from window to well wall
- Allow window to fully open
- Provide access to grade level or have a fixed ladder for exit
Window requirements: minimum 0.35 sq m openable area, minimum 380mm height AND width simultaneously in the openable portion, maximum 1,000mm sill height from finished floor.
Window Well Drainage — Critical for Ontario Clay Soils
Window well flooding is a leading cause of GTA basement water infiltration. Proper drainage is mandatory:
Minimum: 150mm washed gravel at well bottom extending down to weeping tile system. Preferred: drain pipe from well bottom to interior sump or exterior drainage system. Covers: polycarbonate covers ($100-$300) significantly reduce water infiltration and debris.
Window Well Materials
- Galvanized steel: $150-$400 per well. Most common, 15-20 year lifespan in Ontario soil.
- Polycarbonate/plastic: $200-$500 per well. Will not corrode.
- Custom concrete/stone: $500-$2,000 per well. Most durable and attractive.
Full Installation Cost (GTA 2026)
Complete egress window upgrade including foundation cut, structural lintel, egress window, steel well, gravel drainage, and cover: $2,500-$5,500 per window.
Full guide: Ontario Window Well and Egress Guide 2026 - Codes, Drainage and Installation Costs – Telegraph