Types of Attic Insulation: Pros and Cons

Understanding the Importance of Attic Insulation

Before diving into the specifics, it’s crucial to understand why attic insulation is so vital. The primary function of insulation is to provide a barrier that reduces heat flow between the inside and outside of your home. During winter, it keeps the heat inside, and in summer, it prevents the hot outside air from entering, maintaining a comfortable indoor climate.

The effectiveness of insulation is measured by its R-value, which indicates the material’s resistance to heat flow. The higher the R-value, the better the insulation’s performance. Different insulation materials offer varying R-values, so choosing the right one can significantly impact your home’s energy efficiency.

Types of Attic Insulation

Let’s explore the most common types of attic insulation available today, including their pros and cons.

1. Fibreglass Batt Insulation

Fibreglass batt insulation is one of the most traditional and widely used forms of attic insulation. It is made from fine strands of glass fibres, usually bound together into sheets or rolls. This type of insulation is easy to handle and install, making it a popular choice among DIY enthusiasts.

Pros of Fibreglass Batt Insulation

• Affordability: Fibreglass batts are relatively inexpensive compared to other insulation types, making them an attractive option for budget-conscious homeowners.
• Ease of Installation: These batts are straightforward to install, especially in spaces with regular shapes. Many homeowners opt to install fibreglass batts themselves, saving on labour costs.
• Availability: Fibreglass insulation is widely available at most home improvement stores, making it easy to find and purchase.

Cons of Fibreglass Batt Insulation

• Lower R-Value: Compared to other insulation types, fibreglass batts have a lower R-value, meaning they are less effective at insulating your home.
• Moisture Issues: Fibreglass batts do not perform well in damp conditions. If they get wet, their insulation properties diminish, and they can become a breeding ground for mould.
• Potential Health Risks: The glass fibres can irritate the skin, eyes, and respiratory system, so protective gear is essential during installation.

2. Blown-In Fibreglass Insulation

Blown-in fibreglass insulation is similar to fibreglass batt insulation but comes in a loose-fill form that is blown into the attic space using a special machine. This method allows the insulation to fill gaps and cover irregular areas more effectively than batts.

Pros of Blown-In Fibreglass Insulation

• Better Coverage: Blown-in insulation can cover areas that batt insulation might miss, including small crevices and irregular spaces, leading to better overall insulation.
• Improved Air Sealing: By filling gaps more thoroughly, blown-in fibreglass can reduce air leaks better than batts, helping to improve your home’s energy efficiency.

Cons of Blown-In Fibreglass Insulation

• Settling Over Time: Over time, blown-in insulation can settle, reducing its R-value and effectiveness.
• Professional Installation Recommended: While DIY installation is possible, it is more challenging and often requires renting specialised equipment, which might make hiring a professional a more viable option.

3. Blown-In Cellulose Insulation

Blown-in cellulose insulation is made from recycled paper products treated with fire retardants. Like blown-in fibreglass, it is applied using a blowing machine, making it suitable for covering irregular spaces in the attic.

Pros of Blown-In Cellulose Insulation

• Eco-Friendly: Made from recycled materials, cellulose insulation is one of the most environmentally friendly insulation options available.
• Higher R-Value: Cellulose typically offers a higher R-value than fibreglass, providing better insulation performance.
• Good for Soundproofing: Cellulose insulation has excellent soundproofing qualities, which can be beneficial if you live in a noisy area.

Cons of Blown-In Cellulose Insulation

• Moisture Sensitivity: Like fibreglass, cellulose insulation can lose its effectiveness if it gets wet, and it may promote mould growth.
• Settling Over Time: Cellulose insulation can also settle, leading to a reduction in its insulating properties over time.

4. Spray Foam Insulation

Spray foam insulation is a modern and increasingly popular choice for attic insulation. It is applied as a liquid that expands into a foam, filling gaps and crevices. There are two main types of spray foam insulation: open-cell and closed-cell.

Pros of Spray Foam Insulation

• High R-Value: Spray foam has one of the highest R-values per inch of any insulation material, making it extremely effective at maintaining your home’s temperature.
• Air and Moisture Barrier: Unlike other insulation types, spray foam acts as both an insulator and an air/moisture barrier, providing superior protection against air leaks and moisture infiltration.
• Long-Lasting: Once installed, spray foam insulation remains effective for many years without the need for maintenance.

Cons of Spray Foam Insulation

• High Cost: Spray foam insulation is one of the most expensive insulation options, both in terms of materials and installation costs.
• Professional Installation Required: Proper installation of spray foam requires specialised equipment and expertise, so it’s not a DIY-friendly option.
• Potential Health Risks: The chemicals used in spray foam can be hazardous during installation, requiring careful handling and adequate ventilation.

5. Rigid Foam Board Insulation

Rigid foam board insulation is made from foam plastics such as polystyrene, polyisocyanurate, or polyurethane. These boards are cut to fit between attic rafters or laid over the attic floor, providing a solid layer of insulation.

Pros of Rigid Foam Board Insulation

• High R-Value: Rigid foam boards offer a high R-value, making them effective in both warm and cold climates.
• Moisture Resistance: Foam boards are resistant to moisture, reducing the risk of mould growth and maintaining their insulating properties even in damp conditions.
• Durability: Once installed, rigid foam boards are durable and long-lasting, requiring minimal maintenance.

Cons of Rigid Foam Board Insulation

• Difficult Installation: Installing rigid foam boards can be labour-intensive and time-consuming, especially in irregularly shaped spaces.
• Higher Cost: While not as expensive as spray foam, rigid foam boards are still more costly than fibreglass or cellulose insulation.

Choosing the Best Type of Insulation for Your Attic

Selecting the right type of attic insulation depends on several factors, including your budget, climate, and whether you plan to install it yourself or hire a professional. Here’s a quick guide to help you decide:

Consider Your Climate

• Cold Climates: If you live in a colder region, insulation with a higher R-value, such as spray foam or rigid foam boards, might be more effective at keeping your home warm.
• Moderate Climates: In milder climates, fibreglass or cellulose insulation may provide sufficient insulation without the higher cost of spray foam.

DIY or Professional Installation?

• DIY-Friendly: If you’re planning to install the insulation yourself, fibreglass batts or blown-in fibreglass might be your best options due to their ease of installation.
• Professional Installation: For more complex insulation types like spray foam or rigid foam boards, it’s advisable to hire a professional to ensure proper installation and maximise energy efficiency.

Budget Considerations

• Budget-Friendly Options: Fibreglass batts and blown-in fibreglass are generally the most affordable options, making them suitable for homeowners on a budget.

Long-Term Investment: While more expensive upfront, spray foam insulation can offer significant energy savings over time, making it a worthwhile investment for those with a higher budge