Reflectix Vs. Foam Board (Compared)

Insulation is mandatory for all properties. As you are shopping for an insulation material, the first thing that usually comes to mind is a foam board or rigid foam, as it’s popularly known in most stores.

However, as you examine the thick sheets of foam board, the store attendant or a colleague may recommend something much thinner and lighter, Reflectix.

If you are stuck choosing between these two insulation materials, here is an in-depth comparison of Reflectix vs. foam board that will help you make an informed decision.


What is Reflectix?

The key highlight of Reflectix insulation is how thin and neat it is. If you are used to foam boards, you can testify to how bulky and dirty they get, especially during installation. Though not as popular as foam board, Reflectix is a decent insulation material. It has an R-value of up to 21.

Reflectix provides double insulation. It is packaged in thin rolls of a shiny and reflective foil-like wrap. It is made purely of plastic.

It measures 5/16 inches thick and weighs 1.25lbs per square foot. It’s super thin and lightweight. That’s why it can conform to various shapes and designs.

Before we get deeper into our comparison of Reflectix vs. foam board, it’s important to know that Reflectix isn’t a replacement for foam board.

If you are insulating your home, you can use Reflectix to supplement the insulation offered by foam board or other types of insulation, such as fiberglass. Reflectix also works best in tight areas where thick foam boards can’t fit.

You can use Reflectix in areas that often go without insulation due to prohibitions. That’s one of its main selling points.

For instance, if you have a shop that gets cold or hot. You can staple some Reflectix on the roof, which should provide sufficient insulation. This can be done in home garages that also double as workshops.

In some instances, Reflectix can also help with stopping airflow. However, if you have an area where cold air is blowing, the best option would be caulking.

Anyway, this is a DIY hack popular amongst homeowners. Due to its flexible design, Reflectix can also be wrapped around heating vents and pipes to maximize efficiency.

Another application of Reflectix is that it can be used as a house wrap. This material is highly resistant to mold and is effortless to clean.

Styrofoam insulation

What is Foam Board?

When it comes to insulation of buildings, foam board is the number one go-to product. Not only is it very effective at insulation, but it’s easy to use, and it’s a favorite material for DIY enthusiasts.

Foam board is available in 4×8 sheets. However, you can get it in smaller sizes. The thickness of the foam board ranges from 0.25 to 2 inches. Therefore, you can get a thickness suitable for your insulation needs.

Foam board is a better insulation material than other options, such as fiberglass. On a comparison scale, it has a higher R-value and is resistant to moisture.

If you are considering foam board insulation, you need to familiarize yourself with the three different types that exist;

• Expanded Polystyrene: Also known as EPS, this is a common insulation material used in packaging. A good example of EPS is a disposable coffee cup.

It is the most affordable foam board in the market and has the least R-value, which is 4 for every inch of thickness. You can use this type of foam board on wall siding, foundation, and roof.

• Extruded Polystyrene: This is the most common option. They are blue or pink rigid foams that you will find in most stores. Even though the thickness of Extruded Polystyrene varies, they are thicker than the expanded variant.

The R-value is higher and measures 5 per inch of thickness. You can get this board with either groove or tongue edges depending on whether you need to restrict air movement. Extruded Polystyrene works best as an insulation for the foundation.

• Polyiso – The last type of foam board is Polyiso which has a higher R-value of 6 per inch of thickness. Polyiso is also the most expensive type of foam board, and it comes with a foil on one side to reflect heat. You can get Polyiso in various thickness levels. It can be used in the attic, siding, or over-house sheathing.

Foam boards can be used on both interiors and exteriors. It is moisture resistant. Therefore, you don’t have to worry about the foam board getting wet.

Therefore, you can use it outside beneath the wrap or inside a basement foundation. Installation of foam board is pretty straightforward.

You only need a utility knife or a masonry blade to cut it. To adhere the foam board to a surface, screws are more effective.

How Are They Different?

• R-value

Reflectix doesn’t have a particular R-value. It differs depending on the application. The R-value of 21 is applicable when two layers of Reflectix are used beneath a radiant floor heating.

When used for masonry works, the R-value is 4.75 per square foot. The R-value of Reflectix jumps to R-14 when used on exterior walls. Make sure that you confirm Reflectix’s stated R-values depending on the application.

On the other hand, the Foam board’s R-value differs depending on the type. We have mentioned that Expanded Polystyrene has an R-value of 4 per inch of thickness. Extruded Polystyrene has an R-value of 5, and Polyiso has an R-value of 6.

• Application

Reflectix works more as an additional layer of insulation over foam board or fiberglass. It can’t be used as a primary insulation material.

There are a few exceptions, however. If insulation is prohibited in a particular area, Reflectix can be used to facilitate energy efficiency. It can also be used in hard-to-reach areas.

Foam Board is an insulation material that has a wide range of applications. It can be used in the foundation, under walls, or house wrap. Due to its moisture resistance, Foam board can be used outdoors.

• Soundproofing

Reflectix claims to have some soundproofing properties. However, Reflectix can’t offer any significant soundproofing.

It’s too thin and light to absorb any sound from inside or outside the building. Therefore, if you are considering using Reflectix, don’t expect any significant soundproofing capabilities.

Foam boards, on the other hand, are perfect sound absorbers. They prevent bouncing and reverb. You will get better soundproofing from foam board than Reflectix.

• Flammability

Reflectix has a Class A fire rating. This means it has superior fire protection. Foam boards are flammable unless they have been coated with mastic.

How Are They Similar?

• Easy to Install

Even though Reflectix is flexible and foam board is rigid, both are super easy to install. With Reflectix, you only need to measure and cut it into smaller fitting pieces. With foam board, you can cut it with a utility knife and fit it with screws.

• Both Promote Energy Efficiency

You are assured of maximum energy efficiency if you have either Reflectix or foam board on your walls and roof. These two will prevent heat from dissipating through the walls and vice versa for heat and cold air from outside.

Pros of Reflectix

• Easy to use

• Non-flammable and safe

• Has a high R-value

• It can be used on a wide range of applications

• Easily available

Cons of Reflectix

• It can’t be used as an independent insulation material

• It is not soundproof

Pros of Foam Board

• Offers impressive insulation

• It can absorb sound and reverb

• Widely available

• Moisture resistant

• Easy to cut and install

Cons of Foam Board

• It is not as flexible as Reflectix

• It’s challenging to install in hard-to-reach areas

Which is Better? Reflectix or Foam Board

Comparing Reflectix and foam board is a bit tricky because they are not the same. Reflectix is designed to insulate areas that have been prohibited or are hard to reach. It’s also used to complement foam board insulation or fiberglass matt.

On the other hand, foam board is a popular insulation material that is fairly easy to install and moisture-resistant. When comparing these two options, your decision should be guided by how and where you intend to use them.

If you are insulating a building from scratch, go with foam board. But if you need additional insulation, you can use Reflectix.

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