What insulation is best for walls?

The best wall insulation for Ottawa homes depends on your specific situation, but fiberglass batts, spray foam, and mineral wool are the top performers for our climate. Each has distinct advantages for different renovation scenarios and budgets.

Fiberglass batts remain the most popular choice for Ottawa renovations, offering excellent value at $0.50-1.50 per square foot installed. They're ideal for standard 2x4 or 2x6 stud walls and work well in our climate when properly installed with a vapor barrier. The key is ensuring no gaps or compression, which can reduce effectiveness by up to 50%. For Ottawa's heating season, R-12 to R-20 is typical for wall applications.

Spray foam insulation provides superior performance but costs significantly more at $2.50-4.50 per square foot. Closed-cell spray foam offers both insulation and air sealing in one application, making it excellent for older Ottawa homes with air leakage issues. It's particularly valuable in heritage homes in areas like the Glebe or New Edinburgh where irregular framing makes batt installation challenging. Open-cell spray foam costs less but requires a separate vapor barrier.

Mineral wool (Roxul) sits between fiberglass and spray foam in both performance and cost at $1.50-2.50 per square foot. It's naturally fire-resistant, doesn't absorb moisture, and maintains its R-value even when wet - important for Ottawa's freeze-thaw cycles. Many contractors prefer it for basement renovations where moisture can be a concern.

Ottawa-specific considerations include our 4-foot frost line and significant temperature swings. The Ontario Building Code requires minimum R-12 for above-grade walls, but R-20 or higher is recommended for energy efficiency. Vapor barriers are mandatory on the warm side of the insulation to prevent condensation issues during our cold winters.

Professional installation is crucial regardless of material choice. Poor installation can reduce insulation effectiveness dramatically and create moisture problems. For electrical work during insulation upgrades, remember that ESA permits are required, and only licensed contractors can modify wiring around new insulation.

Next steps: Assess your wall construction type, budget, and whether you're doing a full gut renovation or working around existing finishes. Get quotes from multiple insulation contractors, and ensure they understand Ottawa's climate requirements and building code compliance.