If you’re a homeowner in Toronto, Ottawa, or anywhere across Ontario, understanding R-value requirements for attic insulation isn’t just about building code compliance—it’s about protecting your home from our brutal winters and keeping energy bills under control. With Ontario temperatures regularly dropping to -20°C or lower, proper attic insulation is your home’s first line of defense against heat loss.

The Ontario Building Code now requires R-60 minimum for attic insulation in new construction and major renovations. This represents a significant increase from older standards (R-40 was common in homes built before 2012), reflecting the province’s push toward better energy efficiency and reduced heating costs for homeowners.

What Does R-Value Actually Mean?

R-value measures thermal resistance—how well a material resists heat flow. The higher the R-value, the better the insulation performance. In Ontario’s climate, this matters enormously because heat naturally moves from warm spaces (your heated home) to cold spaces (the frigid attic in winter).

Think of R-value like layers of winter clothing. One thin jacket (R-20) won’t cut it in a Toronto February. You need multiple layers—base layer, sweater, heavy coat—to stay warm. Your attic insulation works the same way.

Why Does Ontario Require R-60 for Attics?

Ontario’s building code evolves based on energy research and climate data. R-60 became the standard because:

Heat rises: Up to 25-30% of home heat loss occurs through the attic in under-insulated homes. That’s money literally floating through your roof.

Climate extremes: Ontario experiences temperature swings from -30°C winter nights to +35°C summer days. R-60 insulation handles both extremes, keeping heat in during winter and out during summer.

Energy costs: Natural gas and electricity prices continue climbing. Better insulation = lower monthly bills. Homeowners with R-60 attics save $300-600 annually compared to R-40.

Environmental mandates: Provincial energy efficiency targets drive stricter building codes. R-60 helps Ontario meet greenhouse gas reduction goals.

How Do You Achieve R-60 in Your Attic?

Several insulation materials can achieve R-60, but spray foam insulation offers distinct advantages for Ontario homes:

Spray Foam (Closed-Cell): R-6 to R-7 per inch means you need about 9-10 inches to hit R-60. Spray foam expands to fill every gap and crack, creating an air-tight seal that prevents drafts and moisture infiltration. It also adds structural strength to roof decking.

Fiberglass Batts: R-3.5 per inch requires roughly 17 inches of material. Gaps around joists, wiring, and ductwork reduce effectiveness. Fiberglass also absorbs moisture over time, losing R-value.

Blown-In Cellulose: R-3.7 per inch means 16+ inches needed. Settles over time, requiring periodic topping up. Can absorb moisture in humid attics.

Blown-In Fiberglass: Similar to cellulose but doesn’t settle as much. Still requires significant depth and doesn’t air-seal like spray foam.

For Toronto-area homes, closed-cell spray foam is increasingly popular because it handles Ontario’s freeze-thaw cycles, blocks moisture, and provides maximum R-value in minimal space—crucial for homes with low attic clearance.

Do Older Homes Need to Upgrade to R-60?

The R-60 requirement applies to new construction and major renovations. Existing homes aren’t legally required to upgrade, but many Ontario homeowners choose to for financial and comfort reasons:

Homes built before 2000 typically have R-20 to R-40 attic insulation
Upgrading from R-30 to R-60 can cut heating costs by 30-40%
Improved comfort: fewer cold spots, more consistent temperatures
Better resale value: energy-efficient homes sell faster and for more

Ontario’s Home Energy Rebate Program (HER+) offers grants up to $5,000 for insulation upgrades, making R-60 retrofits more affordable for existing homes.

How to Check Your Current Attic R-Value

Curious what R-value your attic currently has? Here’s how to check:

Safely access your attic (use proper ladder safety)
Measure insulation depth between joists using a ruler or tape measure
Identify material type (spray foam, fiberglass batts, blown-in)
Calculate approximate R-value:
- Spray foam: depth (inches) × 6.5 = R-value
- Fiberglass: depth (inches) × 3.5 = R-value
- Cellulose: depth (inches) × 3.7 = R-value

If you’re seeing 6 inches of fiberglass (R-21) or even 12 inches (R-42), you’re well below current code and likely overpaying for heating.

Ready to Upgrade Your Attic Insulation?

Whether you’re building new, renovating, or simply want to cut energy costs in your existing Toronto or GTA home, achieving R-60 with professional spray foam insulation delivers immediate comfort and long-term savings.

Spray Foam Kings provides free attic assessments across Ontario, helping homeowners understand their current R-values and upgrade options. Our certified installers ensure code-compliant, high-performance insulation that stands up to Ontario’s extreme weather.

Contact Spray Foam Kings today:
📞 Call or text: 647-641-6881
🌐 Learn more: Energy Efficiency Services
📍 Find us: Google Business Profile
💰 Rebates: Check available grants

Stay warm, save money, and bring your Ontario home up to modern energy standards with R-60 attic insulation.