Blown-In Insulation for Walls: Keeping Ottawa Homes Comfortable

Beyond the Attic: The “Drill and Fill” Revolution

While attic insulation delivers the biggest energy savings, walls often represent the next largest source of heat loss in Ottawa homes. Many properties in neighborhoods like Westboro, the Glebe, Rockcliffe, or older parts of Orleans and Kanata were built with empty or minimally insulated wall cavities. Tearing down drywall for traditional batts is expensive, disruptive, and impractical.

This is where wall blown-in insulation—commonly called the “drill and fill” method—provides a game-changing retrofit solution. Small holes are drilled, high-density insulation is injected, and the holes are seamlessly patched. The result: dramatically improved comfort, lower energy bills, and a quieter home without major renovations.

At Bison Insulation, our professional blown-in insulation services in Ottawa include expert wall retrofits tailored to local homes.

Why Wall Insulation Matters in Ottawa’s Climate

Ottawa’s extreme temperature swings and windy conditions drive significant heat loss through exterior walls. Studies from Natural Resources Canada show that uninsulated or poorly insulated walls can account for 20-35% of a home’s total heat loss.

Older homes (pre-1980s) frequently have:

• Empty cavities (no insulation at all)
• Thin or settled original material
• Gaps around wiring, plumbing, and framing

Upgrading walls with dense-pack blown-in insulation creates a continuous thermal barrier, reducing drafts, stabilizing indoor temperatures, and cutting energy costs substantially.

The Drill-and-Fill Process: Minimally Invasive and Highly Effective

Step-by-Step Installation

1. Assessment: We inspect siding, interior finishes, and wall structure to determine the best approach—exterior (through siding) or interior (through drywall).
2. Drilling: Small 2-3 inch holes are strategically placed in each stud bay (usually one or two per cavity).
3. Dense-Pack Injection: Specialized equipment blows insulation at high pressure, ensuring tight packing (3.5-4 lbs per cubic foot for cellulose).
4. Verification: Technicians check fill completeness using probes or infrared tools.
5. Patching: Holes are plugged and finished to match existing surfaces—often invisible after painting.

Most homes complete in 1-3 days with minimal disruption.

Exterior vs Interior Approach

• Exterior (preferred): Drilling through siding or brick preserves interiors. Ideal for finished homes.
• Interior: Used when exterior access is limited or siding is delicate.

Our teams recommend the least invasive option for your property.

High-Density Packing: Preventing Settling and Voids

The Problem with Low-Density Fill

Loose or low-pressure installation can settle over time, leaving empty spaces at the top of walls and reducing effectiveness.

Dense-Pack Advantage

High-pressure injection achieves manufacturer-specified density, creating a solid mass that resists settling for decades. This delivers consistent R-values (typically R-13 to R-15 for 2×4 walls, R-19+ for 2×6) and superior air sealing.

Dense-pack cellulose also conforms around obstacles like wiring and plumbing, eliminating gaps that batts often leave.

Immediate Benefits: Draft Elimination and Consistent Comfort

Stopping Mysterious Drafts

Uninsulated walls allow wind-driven air infiltration, creating cold spots near baseboards, outlets, and windows. Residents often feel unexplained breezes even with closed windows.

Dense blown-in insulation blocks these pathways, making rooms feel “solid” and draft-free. Upper floors especially benefit, as wall upgrades complement attic work for whole-home comfort.

Even Temperatures Throughout

No more hot upstairs bedrooms in summer or freezing exterior rooms in winter. Walls become a stable thermal buffer, reducing HVAC workload and temperature swings.

Enhanced Soundproofing for Urban Living

Ottawa’s vibrant neighborhoods come with noise—traffic on Bank Street, the 417, or nearby construction. Dense-pack cellulose excels at sound absorption, significantly reducing external noise transmission through walls.

This creates a quieter, more peaceful indoor environment—perfect for home offices, nurseries, or relaxation.

Fire Safety Improvements in Older Homes

The Risk in Balloon-Frame Construction

Many pre-1940s Ottawa homes use balloon framing, where wall cavities run continuously from foundation to attic. These act like chimneys during fires, allowing rapid flame spread.

How Blown-In Insulation Enhances Safety

Fire-retardant treated cellulose (borates) fills these voids, slowing flame propagation and smoke movement. While not fireproof, it provides critical extra evacuation time.

Fiberglass options are naturally non-combustible. Both improve overall fire resistance compared to empty cavities.

Material Choices for Wall Retrofits

Dense-Pack Cellulose

• 85%+ recycled content
• Superior air sealing and soundproofing
• Moisture-regulating properties
• Pest-resistant borate treatment
• R-value: ~3.7-3.8 per inch

Most popular for Ottawa wall retrofits due to performance in variable humidity.

Blown-In Fiberglass

• Non-combustible
• Minimal settling
• Good for allergy-sensitive homes
• R-value: ~3.2-4.0 per inch

Excellent alternative when fire rating is priority.

Mineral Wool (Rockwool) Options

Occasionally used for premium sound and fire performance.

Our experts recommend based on your home’s age, construction, and goals.

Energy Savings and ROI for Wall Insulation

Wall retrofits typically reduce total energy use by 10-25% when combined with attic upgrades. Annual savings often reach $400-800, with payback in 7-12 years—faster with available rebates.

Benefits compound with existing attic insulation, creating a complete envelope.

Compatibility with Other Upgrades

Wall blown-in pairs perfectly with:

• Attic top-ups or full installs—see our attic insulation in Ottawa
• Rim joist sealing using spray foam insulation in Ottawa
• Floor insulation over basements or garages via floor insulation in Ottawa

When Removal or Remediation is Needed First

If walls contain old, damaged, or vermiculite insulation (potential asbestos risk), safe removal is required. Our insulation removal in Ottawa handles this professionally.

Moisture-damaged walls may need mold removal in Ottawa before insulating.

Ideal Candidates for Wall Blown-In Insulation

• Homes built before 1980 with little/no wall insulation
• Properties with high energy bills despite attic upgrades
• Drafty or noisy older homes
• Heritage properties wanting efficiency without altering exteriors
• Homeowners planning long-term residency

Professional Installation: Essential for Wall Retrofits

Wall dense-pack requires specialized equipment and expertise:

• Proper pressure and nozzle technique
• Complete fill verification
• Clean, professional patching
• Compliance with building codes

DIY attempts often result in voids, settling, or exterior damage—costing more to fix later.

Real Results from Ottawa Homeowners

Local clients report:

• “The house finally feels warm all winter—no more cold walls”
• “Traffic noise from Rideau Street is barely noticeable now”
• “Our heating bill dropped noticeably after walls and attic”
• “Exterior holes are invisible—looks exactly the same”

These outcomes reflect proper dense-pack execution.

Conclusion: Complete Your Home’s Thermal Envelope

Wall blown-in insulation transforms older Ottawa homes from drafty and inefficient to comfortable and modern—without major renovations. The drill-and-fill method delivers lasting performance, safety enhancements, and significant savings.

Combine it with attic upgrades for maximum impact. Don’t stop at the roof—insulate your walls for true year-round comfort.

Ready to eliminate drafts and lower bills? Contact Bison Insulation for a free wall assessment. Visit our homepage to explore solutions and schedule your consultation today.

Invest in your walls—enjoy the difference immediately.