What Is Foam Board Insulation Used For? (Benefits and Types)

If you’re looking to remodel your walls, foam board insulation will be your best friend. From the different types of foam boarding, to various uses, the ultimate mission of foam board is to ensure your home is well ventilated with clean air.

Foam board insulation uses lightweight material to fill in open cavities of walls, roofs, and other interal structures. It improves air quality and circulation in your home, and keeps it clean from excess moisture and mold.

Keeping your house in tip-top shape is important to you, so keep reading to learn more about the uses of foam board insulation.

What Is Foam Board Insulation?

As the name suggests, square boards made from foam material are used as mechanisms for creating clean, fresh air, and helping it to circulate throughout your vents and entire home. When looking for an alternative to fiberglass, foam board insulation is the next best option.

You may be wondering if you’ll need a professional for proper insulation, and the answer is yes and no. There are installers who are skilled at lining your systems with foam boards, or you can use it as a do-it-yourself project!

Because of their shape and size, placing them throughout your walls can be an efficient way of developing cleaner air in your ventilation system and your home.

How Does Foam Board Insulation Work?

According to a report by the United States Department of Energy, foam board insulation has the strong ability to create quality thermal resistance via reducing heat conduction.

Those words sound fancy, so in Layman’s terms, the foam lowers the surrounding heat in the environment which makes the air lighter and easier to move around in a faster and smoother form.

This happens because of small pores within the foam boards that allow for only a certain amount of air to go through at a time, keeping it clean as it flows through various vents and pipe systems.

Foam board insulation also uses structural Earth elements like steel studs or wood for improved thermal resistance and decreased air temperatures.

What Are The Advantages of Foam Board Insulation?

Because of tiny pores within the material, foam board insulation comes packed with major benefits. Take a look at the top three advantages of using this form of insulation:

Provides air-sealed protection: It tightens up corners by filling them with the foam. This generates a more comfortable setting and cooler air flowing through your home.
Decreases humidity: When air becomes stuffy or too hot, it creates a warm and moist environment for mold to grow. Foam board significantly reduces humidity by moving around cooler air.
Creates a smoke barrier: Based on the classification, foam boards can be fire-retardant, slowing the radiation of heat that creates flames from light sources like electrical wires and plug outlets. Foam board provides little oxygen, therefore, little-to-no fire.

The fun doesn’t stop there. Due to its ability to move cool air around and keep the warm air from piling up, foam board can also keep bugs away that crave and feast on bacteria made by warm air. With its small holes, in addition to heat, it also allows for minimum sound to travel through walls, thus reducing noise levels.

What Are The Disadvantages of Foam Board Insulation?

The shortcomings of foam board insulation typically happens after years of usage. However, the disadvantages are all the same, so here’s what you can expect:

Collection of moisture: If the air isn’t being pushed around, it becomes stagnant within the holes of the foam. Within several years, the trapped moisture can create various bacteria that will need professional service for cleaning.

Air leakage: After years of using the same foam boards, the once tiny pores will begin to stretch because of what is trapped within it. This will cause air to leak out and increase humidity. When this happens, changing the foam is necessary.

Decrease in functionality: Foam board insulation has a high rate of success for the first few decades, but will deteriorate over time. The color of the foam will change, which is an indicator that it’s time to replace the boards.

What Are The Different Types of Insulation Board?

(Rigid) foam board insulation comes in three main types: Expanded polystyrene (EPS), Extruded polystyrene (XPS), and Polyisocyanurate (Polyiso, ISO).

Here’s a brief description of each board:

Expanded Polystyrene (EPS): The most commonly used form because of its versatility. It can be used in walls, roofs, attics, and basements. It also comes in standard grade and GeoFoam brands that are environmentally friendly, with the best Resistance Value.
Extruded Polystyrene (XPS): Comes in different colors like pink, blue, or pink. With a moderate R-Value, XPS are typically used in walls and small-grade applications.It’s thick and semi-permeable, making it more affordable than EPS.
Polyisocyanurate (ISO): Starts off as a liquid form that turns rigid and hardens within a few minutes. Mostly used for roofing insulation, it has permeable and impermeable faces that create a higher-than-standard R-Value, thus, less moisture.

How Long Does Foam Board Insulation Last?

When installed properly, foam board insulation can last for up to 100 years. The boards last this long for several reasons, which tie back to its benefits. The high water resistance of the foam keeps it dry for a long time.

With proper air flow, the pores of the foam stay small while filtering out the heavy air from the light air, with only the light air passing through. The durability of the boards is a major factor that enhances its longevity. It’s firm and strong, with no hassle or movement once it is installed.

Correct insulation is the key in making the foam boards last for as long as possible. If you choose to use it as a DIY project, consult a professional for accuracy. You should know that there are factors that can deter the length of the boards life, so ensure that the boards are used in the right areas with the right conditions.

How Much Does Foam Board Insulation Cost?

The average cost for foam board insulation is approximately $5,000, with a low cost of around $2,500 and a high of about $7,500 based on a 1800 square foot house.

Prices are formed on a per square foot measurement and based on your home, each square foot can cost between $0.25 and $1.40, with an average of $0.75 in accordance to 8×4 foot boards.

Here’s the important thing to know when it comes to pricing of foam board insulation: the price is based on the thickness of the board. Additionally, the cost of foam board insulation will vary based on whether they are faced or unfaced, as well as the R-Value, the higher it is, the higher the cost.

Prices are also based on which room is being insulated. Attics are the most expensive ranging between $2.50 and $7.50 with an average of $5, with the garage being the most affordable at $0.90 per square foot.

When Should You Use Foam Board Insulation?

The greatest benefit of foam board is its ability to resist moisture and keep dry, so you should use foam board insulation when and where there are high amounts of moisture.

Rooms in homes that are susceptible to extreme moisture are basements, attics, and the exterior of your house. Foam boards can fill in cavities and crawl spaces in these locations to keep excess air from moving through to keep moisture and water from forming.

Use this insulation in walls to protect the inside of them from water and rain that formulate outside of your house, as well as beneath a house wrap or inside of a basement against the foundation of your home. Foam board insulation can be quite pricey, so be sure to only use when and where there is the most moisture.

You should not use this type of insulation in dry places like on the interior of your home, bedrooms, or near an air conditioning system. It would be a complete waste of money and a professional will be able to provide you with other options for dry areas.

Do You Have To Cover Foam Board Insulation?

The largest advantage – and downfall – of foam board insulation is its ability to withstand UV rays from the sun. When the rays hit the board, they tend to deteriorate the material extremely slowly, but surely over time, which is why it is recommended to cover foam board insulation if and/or when it is exposed to the sun.

It’s OK if you don’t cover them immediately because they are made to be durable, but you definitely want to cover the foam boards within 1-2 months of installation. This is typically how long it can take to cover a house with the foam, so it’s right on schedule and will still last the tens of decades that it lives.

Now that you know that foam board insulation should be covered, you may be wondering what to cover it with. Typically, drywall is used to shield foam board insulation because of its low-to-affordable pricing and fire resistant qualities.

There are two types of drywall:

Standard: For finishes of walls after insulation is installed.
Fire-Resistance: Treated with environmentally-safe chemicals for extra heat protection.

Either form of drywall is suitable for covering foam board, and should be applied once the installation is complete.

Does Foam Board Need A Vapor Barrier?

Vapor barriers are highly recommended for foam boards because they create a protective structure that keeps extra moisture from entering the foam.

Diffusion of vapor is key to extending the longevity of the foam boards’ functionality and keeping your home from developing patches of mold in small, exposed cavities of your home.

Foil-faced polyisocyanurate is a great option as a vapor barrier because there are no holes in it and the foil creates an impermeable barrier. Expanded polystyrene also creates a thick enough barrier to stop vapor steamed moisture from coming in.

How Long Can Foam Board Be Exposed To Weather?

With proper insulation, you have approximately 30-60 days to leave your foam insulation exposed to weather. Environmental factors like excess sunlight will weaken the foam material over time, as well as spread the small pores open wider at a faster rate, reducing the effectiveness of the insulation.

Water is a major determining factor of how fast the foam material will deteriorate, and how soon the insulation will fill with water, causing mold to form and potentially spread due to ventilation movement.

Be sure to have your foam boards covered with standard or fire-resistant drywall to ensure that your insulation continues working for the next 100 years.

How Thick Should My Foam Board Insulation Be?

Foam boards are very thick for the purpose of improved insulation from environmental factors. The average thickness of foam board insulation ranges between ⅜” and 2.5”.

Thickness is also based on the dimension of the foam boards, which can range from 2’x8’ and 4’x8’, which are the two standard sizes, although custom sizes are available based on the company you choose to use.

Thickness can also be correlated to R-Value, as thicker boards have a higher R-value. ISO or Polyiso has the highest R-value per inch with an average of R-6.6.

Is Foam Board Insulation Good For Soundproofing?

Foam board insulation has the ability to slow down the transfer of sound due to the small porous holes within them. However, foam boards are not the best for soundproofing as they are not dense enough to completely stop soundwaves from passing through them.

The boards will only give a regular thermal insulation with low-to-medium density, where a high density is necessary to refrain high and low frequencies.