# Ontario Basement Waterproofing: Interior vs Exterior — What Works and What It Costs

**URL:** <https://home.renovation.reviews/t/ontario-basement-waterproofing-interior-vs-exterior-what-works-and-what-it-costs/46858>\
**Category:** Ontario\
**Created:** [April 26, 2026, 6:20pm UTC](https://home.renovation.reviews/t/ontario-basement-waterproofing-interior-vs-exterior-what-works-and-what-it-costs/46858 "2026-04-26T18:20:40Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![system](https://home.renovation.reviews/user_avatar/home.renovation.reviews/system/32/77_2.png) [@system](https://home.renovation.reviews/u/system)\
**Post date:** [April 26, 2026, 6:20pm UTC](https://home.renovation.reviews/t/ontario-basement-waterproofing-interior-vs-exterior-what-works-and-what-it-costs/46858/1 "2026-04-26T18:20:40Z")

</div>

Basement moisture is one of Ontario’s most common home problems. Freeze-thaw cycles, high water tables in GTA, and aging weeping tile all contribute. Here is how to approach waterproofing correctly.

**Exterior Waterproofing**  
Excavate to footing, apply waterproofing membrane and drainage board, install new weeping tile, backfill with clear stone. The gold standard. Cost: $15,000-$40,000+ full perimeter. Disturbs landscaping. Required for active foundation cracks or failed weeping tile.

**Interior Drainage System**  
Perimeter drainage channel at interior footing, water directed to sump pit. Manages hydrostatic pressure from inside. Cost: $8,000-$20,000. Less disruptive. Manages water after entry — does not stop it from getting in. Best where exterior excavation is impractical.

**Crack Injection**  
Polyurethane or epoxy injection for isolated active cracks. Cost: $500-$2,000 per crack. Effective for poured concrete wall cracks. Not a drainage system substitute.

**Sump Pump**  
Every waterproofing system needs a reliable sump pump. Battery backup essential — power outages coincide with heavy rain events. Primary + battery backup: $500-$1,500 installed.

**Contractor Vetting**  
Reputable companies offer 25-year transferable warranties. Get 3 quotes. Be wary of companies offering only one solution type.

Share waterproofing quotes and contractor experiences at home.renovation.reviews.