The Pros and Cons of Different Rigid Foam Insulation Types

When it comes to building up a home’s insulation, rigid foam insulation is one of the preferred options to use. There are a variety of different traits of foam board insulation, from its accessibility to its effectiveness, that makes it a key construction component. With this said, there are a variety of different subsets of rigid foam insulation for homeowners, property owners, and construction companies alike to consider. Here is a comparison of all the different options on the table and the different pros and cons of each.

What Does Rigid Foam Insulation Do?

First, let’s give a brief explanation of the purpose of rigid foam insulation. Generally, this serves as a continuous insulation layer, generally applied to the roof and exterior walls. This helps contribute to less lost energy through the framing members, which, in turn, leads to lower energy costs and a more comfortable area in general. In some cases, foam is also placed under basement slabs to lower heat loss via the concrete. 

What separates rigid foam insulation from other types? It’s all in the name. Compared to, say, batt insulation or blown insulation, rigid foam is stronger and doesn’t shift out of place after installation. In addition, it is resistant to water and pests, which is why it is commonly used in crawlspaces and basements. It can also serve as an air barrier if the boards are properly sealed along the edges and joints. Another benefit of it is its versatility. This can easily be cut and glued to fit into areas that have unusual shapes. 

An important term to bring up in this conversation is R-value or thermal resistance. R-value is a metric that determines an insulating material’s resistance to heat flow. The higher the R-value, the better the foam board insulation does at its job. This is generally based on the following factors:

• -Foam insulation board type
• -Thickness
• -Density

Factors like aging, temperature, and the amount of moisture may also be calculated for certain insulation types. 

The Different Rigid Foam Insulation Options

With a basic explanation of the purpose of rigid foam insulation, we can talk about the various types. Each has its ideal applications, but professionals will need to often choose between one or another based on the project/customer needs.

Expanded Polystyrene

Also known as EPS or beadboard, this is generally the best budget option for people who need rigid foam insulation. While it doesn’t have as much R-value as the other options here, you can expect a range of around 3.6 to 4.2 per inch. This makes it a good way to add R-Value in an attic, on top of a roof, or in wall cavities. But if there is a risk of water exposure, invest in a moisture-resistant coating or film.  

Extruded Polystyrene

Also known as XPS or blue board, this is the best fit for any applications below grade. Compared to XPS, it has better moisture resistance, even without coating or films. In addition, it has a higher R-value (roughly 5 per inch) and is denser and more durable. The only drawback is that it generally costs more.

Polyisocyanurate

Also known as ISO or polyiso, this is considered the eco-friendly option when it comes to rigid foam insulation. This contains roughly 9% recycled materials and has a higher R-value, at 6.5 per inch on average. For those concerned about safety and eco-friendliness, the flame retardant in polyiso is less toxic than the types used for other insulations. The drawback is that this is the most expensive of all the options covered here. In addition, it tends to absorb water, making it unsuitable for below-grade applications.

Expanded Polyurethane

Also known as EPU, this is a specific type of rigid foam insulation that’s generally intended for insulated concrete forms. These serve as a replacement to the conventional wooden forms for fresh concrete. These are different from your conventional rigid foam insulation in that they are hollow form blocks, which get left in place as the concrete cures. This allows for insulation as long as the structure’s lifespan. This offers an average R-value of 5.9 per inch and is surprisingly durable. 

Mineral Wool 

This is quite different than all the other options mentioned to this point, largely because it’s not a petroleum-based foam product. Instead, mineral wool is a recycled item created with stone dust from blast furnaces. This gives it a few unique benefits. It’s completely non-toxic and won’t create any off-gas into your home as foam products do. This means that it won’t lose R-value over time and allows for better air quality. Other benefits of mineral wool are that it helps with soundproofing, is completely fireproof, and isn’t impacted by moisture. However, it isn’t an air barrier at all. In addition, it costs more than fiberglass.

At this point, we’ve covered the different facets of your rigid foam insulation options. In some cases, there’s an obvious case where only one type is appropriate for the job that you are doing. In other cases, though, the best choice is a bit more of a flexible decision. You can have two installations that meet the basic requirements, but your decision is more based on what it will cost you, what type of materials are available, or how long it will take to install.

In these cases, it’s important that you fully understand the data on your different insulation choices and what it takes for you to utilize them. The only way for you to gather the data you need for this is through

project management software such as eSub. Trying to figure out how long it will take? Track your employees, equipment, and manhours. Worried about financial costs? Look at your history of bids and actuals to make sure that your quotes still leave a profit for your business.

How eSUB Can Help

eSUB is a cloud-based project management platform built especially for subcontractors. It seamlessly integrates with leading construction software systems so you can easily switch from your current RFI process to a cloud-based system to upgrade RFI process.

eSUB organizes all of your project information in one place, allows for smooth collaboration, and streamlines communication through its intuitive interface. It also works on your mobile, so you can track projects on the go—no matter where or when—and stay up-to-date.

FAQs: Rigid Foam Insulation Types

1. What is the purpose of rigid foam insulation in construction?

• Rigid foam insulation serves as a continuous insulation layer applied to roofs and exterior walls to reduce energy loss through framing members, leading to lower energy costs and increased comfort. It can also be used under basement slabs to lower heat loss.

2. How does rigid foam insulation differ from other insulation types?

• Rigid foam insulation is stronger, doesn’t shift after installation, is resistant to water and pests, and can act as an air barrier when properly sealed. It is also versatile and can be customized to fit unusual shapes.

3. What is R-value, and why is it important in rigid foam insulation?

• R-value is a metric that measures an insulation material’s resistance to heat flow. The higher the R-value, the better the insulation performs. R-value depends on factors like foam board type, thickness, and density, as well as external factors like aging, temperature, and moisture.

4. What are the different types of rigid foam insulation available?

• There are several types of rigid foam insulation, including:
  • Expanded Polystyrene (EPS or beadboard)
  • Extruded Polystyrene (XPS or blue board)
  • Polyisocyanurate (ISO or polyiso)
  • Expanded Polyurethane (EPU)
  • Mineral Wool

5. Which type of rigid foam insulation is the most budget-friendly option?

• Expanded Polystyrene (EPS) is generally the best budget option. While it has a slightly lower R-value, it is cost-effective and suitable for various applications.

6. What is the best rigid foam insulation type for below-grade applications?

• Extruded Polystyrene (XPS) is the best choice for applications below grade. It offers better moisture resistance and a higher R-value.

7. Are there eco-friendly options among rigid foam insulation types?

• Polyisocyanurate (ISO or polyiso) is considered an eco-friendly option as it contains roughly 9% recycled materials. It also has a high R-value, but it may not be suitable for below-grade applications due to moisture absorption.

8. What is unique about Expanded Polyurethane (EPU) rigid foam insulation?

• Expanded Polyurethane (EPU) is intended for insulated concrete forms and remains in place as concrete cures. It offers an average R-value of 5.9 per inch and is exceptionally durable.

9. What makes Mineral Wool insulation different from petroleum-based foam products?

• Mineral Wool is non-toxic, does not emit harmful gases, and maintains its R-value over time. It also offers soundproofing, is fireproof, and is unaffected by moisture. However, it does not act as an air barrier and is generally more expensive than fiberglass.

10. How can project management software like eSUB assist in the decision-making process for rigid foam insulation installation?

• Project management software such as eSUB helps contractors gather essential data, track employees, equipment, and manhours, and analyze financial costs. This data-driven approach ensures that insulation choices are made efficiently and profitably for construction projects.