Best Insulation For Garages in 2025

Insights & Updates | Garage Insulation | Spray Foam Insulation

Insulating your garage is an essential step to ensure energy efficiency and comfort, especially in cold climates like Manitoba. Whether you’re planning to use your garage for storage, as a workspace, or to simply keep your vehicle warm during winter, choosing the right insulation and flooring options, including the Best Insulation For Garages, can make all the difference. Here, we’ll cover some key considerations and answer frequently asked questions to help you get started.

Benefits of Garage Insulation

Adding insulation to your garage delivers multiple benefits:

Energy Efficiency: Prevents heat loss in winter and heat gain in summer, lowering your energy bills.
Comfort: Creates a more stable and comfortable temperature, ideal for workshops or converted living spaces.
Protection: Helps safeguard stored items like tools, vehicles, and perishables from extreme temperature fluctuations.
Noise Reduction: Garage insulation dampens outside noise, making the garage a quieter environment.

6 Factors to Consider When Choosing the Best Insulation For Garages

When choosing insulation, think about:

Wall Construction:

2×4 wall cavities have the capacity to hold up to 3.5 inches of closed cell spray foam (R-18.2) or batt insulation (R-12) to provide insulation.
For increased R-values, 2×6 wall cavities are required, as they can accommodate 5.5 inches of closed cell spray foam (R-28.5) or batt insulation (R-19).

Roof Style:

Sloped Roofs: Insulation should be directly applied to the roof deck for sloped roofs.
Flat Ceilings: For optimal thermal efficiency and cost savings in both the short and long term, a combination of closed cell spray foam insulation and blown-in cellulose can be employed for flat ceilings.

Garage Use:

Heated garages benefit most from spray foam due to its airtightness and efficiency.
Unheated garages may use fibreglass or blown-in insulation as cost-effective options.

Climate:

Colder climates require higher R-values to reduce heat transfer (closed cell spray foam insulation), while milder climates can use lower R-values (batt insulation).
Proper ventilation ensures that moisture doesn’t compromise the insulation or structure of the garage.

Budget & Long Term Efficiency Goals

Fiberglass batts and rockwool batts are more budget-friendly upfront & while spray foam insulation may have higher initial costs, it offers long-term savings when it comes to heating and cooling.

Local Building Codes

Check insulation requirements for garages in your area, including fire safety standards and whether or not you require a fire protective coating on top of your insulation.

Common Types of Garage Insulation

When selecting insulation for your garage, it’s important to consider factors like cavity space, energy efficiency, moisture control, budget and your intended use of the space. Here’s a breakdown of the best insulation options and what to keep in mind:

Closed Cell Spray Foam Insulation For Your Garage Walls & Ceiling

Spray foam is often considered the gold standard for garage insulation due to its high performance and versatility.

Benefits:

Provides the highest LTTR-value per inch (R-5.19), making it ideal for tight spaces like 2×4 walls.
Acts as both an insulator and a vapour barrier, reducing the risk of moisture buildup and mold.
Seals air gaps, improving energy efficiency and reducing drafts.
Adds structural strength to your walls and ceiling.
Provides the highest R-value per inch (LTTR-5.19).

Best For:

Energy-efficient, heated garages and workshops.
Sloped ceilings where airtightness is critical.

Considerations (Based on Desired R-Value & Framing Construction):

2×4 framing: At 3.5 inches thick, the maximum R-Value achieved with closed cell spray foam is R-18.2.
2×6 framing: At 5.5 inches thick, the maximum R-Value achieved with closed cell spray foam is R-28.5.

Closed Cell Spray Foam Insulation For Your Garage Walls & Ceiling

Spray foam is often considered the gold standard for garage insulation due to its high performance and versatility.

Benefits:

Provides the highest LTTR-value per inch (R-5.19), making it ideal for tight spaces like 2×4 walls.
Acts as both an insulator and a vapour barrier, reducing the risk of moisture buildup and mold.
Seals air gaps, improving energy efficiency and reducing drafts.
Adds structural strength to your walls and ceiling.
Provides the highest R-value per inch (LTTR-5.19).

Best For:

Energy-efficient, heated garages and workshops.
Sloped ceilings where airtightness is critical.

Considerations (Based on Desired R-Value & Framing Construction):

2×4 framing: At 3.5 inches thick, the maximum R-Value achieved with closed cell spray foam is R-18.2.
2×6 framing: At 5.5 inches thick, the maximum R-Value achieved with closed cell spray foam is R-28.5.

Fibreglass Batt Insulation

Fibreglass is a more affordable option but comes with certain limitations compared to spray foam.

Benefits:

Lower upfront cost.
Relatively easy to install for DIY projects.

Considerations:

Limited R-value (R-12 in 2×4 walls and R-20 in 2×6 walls).
Does not seal air gaps, which can reduce effectiveness in cold climates.
Susceptible to moisture, which can degrade its performance over time.

Best For:

Garages where immediate cost is a primary concern and airtightness is less critical, like unheated garages.

Considerations (Based on Desired R-Value & Framing Construction):

2×4 framing: At 3.5 inches thick, the maximum R-Value achieved with fibreglass batt insulation is R-12.
2×6 framing: At 5.5 inches thick, the maximum R-Value achieved with fibreglass batt insulation is R-20.

Fibreglass Batt Insulation

Fibreglass is a more affordable option but comes with certain limitations compared to spray foam.

Benefits:

Lower upfront cost.
Relatively easy to install for DIY projects.

Considerations:

Limited R-value (R-12 in 2×4 walls and R-20 in 2×6 walls).
Does not seal air gaps, which can reduce effectiveness in cold climates.
Susceptible to moisture, which can degrade its performance over time.

Best For:

Garages where immediate cost is a primary concern and airtightness is less critical, like unheated garages.

Considerations (Based on Desired R-Value & Framing Construction):

2×4 framing: At 3.5 inches thick, the maximum R-Value achieved with fibreglass batt insulation is R-12.
2×6 framing: At 5.5 inches thick, the maximum R-Value achieved with fibreglass batt insulation is R-20.

Rockwool Insulation

Rockwool is a premium alternative to fibreglass with improved thermal and soundproofing properties.

Benefits:

Slightly higher R-value per inch than fibreglass.
Excellent fire resistance and sound absorption.

Considerations:

More expensive than fibreglass.
Limited R-value (R-12 in 2×4 walls and R-20 in 2×6 walls).
Does not seal air gaps like spray foam insulation, which can reduce effectiveness in cold climates.

Best For:

Homeowners seeking superior fireproofing and soundproofing.

Considerations (Based on Desired R-Value & Framing Construction):

2×4 framing: At 3.5 inches thick, the maximum R-Value achieved with rockwool batt insulation is R-12.
2×6 framing: At 5.5 inches thick, the maximum R-Value achieved with rockwool batt insulation is R-20.

Rockwool Insulation

Rockwool is a premium alternative to fibreglass with improved thermal and soundproofing properties.

Benefits:

Slightly higher R-value per inch than fibreglass.
Excellent fire resistance and sound absorption.

Considerations:

More expensive than fibreglass.
Limited R-value (R-12 in 2×4 walls and R-20 in 2×6 walls).
Does not seal air gaps like spray foam insulation, which can reduce effectiveness in cold climates.

Best For:

Homeowners seeking superior fireproofing and soundproofing.

Considerations (Based on Desired R-Value & Framing Construction):

2×4 framing: At 3.5 inches thick, the maximum R-Value achieved with rockwool batt insulation is R-12.
2×6 framing: At 5.5 inches thick, the maximum R-Value achieved with rockwool batt insulation is R-20.

Blown-In Cellulose & Spray Foam Insulation for Your Garage Ceiling: Hybrid Approach

For flat ceilings, a hybrid approach using Closed Cell Spray Foam Insulation & Blown-In Cellulose Insulation can provide a balance between performance and cost.
Attics requiring both energy efficiency and cost savings.

Benefits:

Closed cell spray foam (2 inches) creates an airtight seal and acts as a vapour barrier.
Blown-in cellulose adds additional R-value (8 inches in addition to closed cell spray foam achieves R-31 for flat ceilings).

Best For:

Flat ceilings with budget constraints.

Blown-In Cellulose & Spray Foam Insulation for Your Garage Ceiling: Hybrid Approach

For flat ceilings, a hybrid approach using Closed Cell Spray Foam Insulation & Blown-In Cellulose Insulation can provide a balance between performance and cost.
Attics requiring both energy efficiency and cost savings.

Benefits:

Closed cell spray foam (2 inches) creates an airtight seal and acts as a vapour barrier.
Blown-in cellulose adds additional R-value (8 inches in addition to closed cell spray foam achieves R-31 for flat ceilings).

Best For:

Flat ceilings with budget constraints.

Garage Door Insulation: A Key Step

Your garage door plays a significant role in maintaining consistent temperatures. If your door isn’t insulated, you could be losing a significant amount of heat. Here are some tips to ensure your garage door contributes to your energy efficiency goals:

Upgrade to an Insulated Door: Consider the replacement or installation of an insulated door as an upgraded choice. Trapp Doors, run by Gerry & Andrea, provides insulated garage doors with R-values that are ideal for the climate of Manitoba, alongside their exceptional services and repairs for overhead doors, including spring repairs and weather sealing.
Sealing Gaps: Even with an insulated door, sealing gaps is essential to prevent drafts. Adding weatherproofing strips, threshold seals, and insulating the frame can significantly reduce heat loss.
Target R-Value: For Manitoba’s cold climate, aim for a door with an R-value of R-12 or higher to maximize energy savings.

Underslab Insulation: An Often Overlooked Opportunity

If you’re planning to heat your garage, insulating the concrete slab can significantly improve energy efficiency. Polyurethane underslab insulating foam (2–3 inches) prevents heat loss through the floor, making the space more comfortable and reducing energy costs. Additionally, our concrete lifting and leveling division, Slab-Jack Kings, specializes in concrete lifting, levelling, void filling, stabilizing, and underslab insulating, offering comprehensive solutions for your garage.

Frequently Asked Questions About The Best Insulation for Garages

How much insulation can I fit in my garage walls?

For 2×4 wall cavities, you can install up to 3.5 inches of spray foam (R-18.2) or fibreglass batts (R-12).
For 2×6 wall cavities, you can go up to 5.5 inches of spray foam (R-28.5) or use fibreglass batts for around R-19.

Which garage insulation is better for Manitoba’s climate: spray foam or fibreglass?

Spray foam is superior for energy efficiency, air sealing, and moisture control, making it ideal for insulating garages in colder climates. Fibreglass is more affordable but less effective in preventing drafts and moisture issues, which can lead to reduced energy efficiency in the long run.

What’s the best way to insulate a garage ceiling with a sloped roof?

Apply 3 inches of closed-cell spray foam directly on the roof deck to achieve an R-value of ~R-17.5 while ensuring airtightness and structural support.

Is it important to insulate my garage door?

Absolutely. An insulated door with weatherproofing can prevent significant heat loss. Look for a door with an R-value of at least R-12 if you live somewhere with a colder climate.

Can I use my attic for storage if I insulate it?

Yes! If you plan to use your attic for storage, closed cell spray foam is the best option because it provides high R-values with less thickness, leaving more usable space.

Should I consider underslab insulation in my garage?

Yes, especially if you’re heating the garage or have in-floor radiant heat. Underslab insulation installed by Slab-Jack Kings reduces heat loss through the floor and improves overall comfort.

By addressing these considerations, you’ll ensure your garage is efficient, durable, and suited to your needs. For any specific questions or if you’re ready for a quote, feel free to reach out. We’re here to help!

Why Choose Cold Country Spray Foam?

As a small, Canadian, family-run business, we take pride in providing expert consultation, sales, and installation of polyurethane spray foam insulation across Manitoba and Northwestern Ontario. Our team of insulation specialists is here to guide you through every step of the process, ensuring you get the highest quality, best insulation for garages. Learn more about spray foam insulation.

Contact Cold Country Spray Foam Today For A Free Garage Insulation Quote

If you’re ready to add garage insulation or upgrade, get in touch with Cold Country Spray Foam. We offer free estimates for spray foam insulation, blown-in cellulose attic insulation, and insulation removal services. Fill out our online estimate request form to start your journey toward a more comfortable, energy-efficient home today!