We built a custom home in Caledon in 2022 and specified ICF (Insulated Concrete Form) for the full basement walls. Three years in, here is what we know.
Why we chose ICF: Our previous house had a conventional poured concrete basement. Despite full interior framing, insulation, and vapour barrier, the basement always felt slightly damp and cool. The interior framing also ate 4 inches of space on every wall perimeter. We wanted a different approach.
Builder resistance: Our first two builders quoted ICF but both said “we prefer poured concrete, ICF is more complicated.” The third builder specialized in ICF (Arxx system) and explained why: the forming requires different skilled labour (not complicated, just different — and their crew was experienced). We went with them.
The ICF system spec: Logix Platinum, 8-inch core (R-32 total wall assembly when you include both foam faces). The walls run from the footing to the top of the foundation — approximately 9 feet of wall height.
Finishing the basement: No interior wall framing required. We applied 2x2 furring strips at 16-inch centres directly to the foam face, then 5/8-inch drywall. Total wall thickness added to interior: 3.5 inches. The furring also allowed us to run electrical horizontally without touching the concrete.
3-year performance numbers:
- January basement temperature (unheated, no mechanical, just passive from house above): 14°C. Our neighbour with similar poured concrete construction: 8°C.
- No condensation on any basement wall surface in 3 winters.
- RH in basement: 42-48% year-round without a dehumidifier.
Our previous house with conventional basement: Required a 70-pint dehumidifier running May–September, RH often reached 65%+ without it.
Construction cost premium vs conventional poured: Our builder estimated $18,000 additional for the full basement ICF vs conventional. We paid zero in separate basement insulation, saved approximately $9,000 in framing and insulation labour, and eliminated the dehumidifier requirement ($300/year for 30 years = $9,000 present value). Net premium: approximately $0 over 30 years.
Three-year verdict: ICF for any finished Ontario basement is the obvious choice. We would specify it again without hesitation.