We knew when we bought our 1997 Mississauga detached that it had EIFS (Dryvit-type) stucco. What we did not know until we did a pre-purchase moisture scan was how extensive the water damage was behind it.
The discovery: A home inspector with a moisture meter found elevated readings at every window perimeter on the east side of the house — the side that takes prevailing rain. Further probing found soft substrate on three of five windows. The sellers disclosed nothing. We negotiated $22,000 off the purchase price and proceeded with remediation after closing.
What we found on removal: The east wall is approximately 900 sqft of EIFS cladding. When the contractor removed it, three of the five window bays had significant OSB sheathing damage — two were fully punky (soft, crumbling) and needed full sheathing replacement over an area of approximately 40 sqft each. The worst window had rot extending to the stud cavity — two studs needed sister-reinforcing.
The repair scope:
- Remove EIFS east wall (900 sqft): included in contract
- Replace damaged OSB sheathing (approximately 140 sqft): $1,800
- Structural repair (studs): $600
- Install new drainage-plane rain screen membrane (Henry BlueskinVP): $2,400 (entire east wall)
- New fibre cement siding (James Hardie Artisan, 7" lap) in place of EIFS: $18,500 installed
- New windows (replaced 3 damaged-frame units): $4,200
- Prime and paint: included in siding contract
- Total: $27,500
Lesson: If you are buying a 1990s home with EIFS, pay $400 for a moisture scan before offer. Not after.
The other three walls appear dry. We are budgeting for those in future years but not rushing.