Pros And Cons Of A Hybrid Insulation System

You were considering flash and batt insulation but were put off by the problems it can create. Can an additional inch of spray foam insulation make the spray foam and batt combination worthwhile?

South Central Services does not install traditional flash and batt insulation: one inch of spray foam with a batt of insulation on top. Instead, our team installs hybrid systems. Hybrid systems are similar to the flash and batt concept. However, our hybrid system has more spray foam insulation, which solves the potential problems of traditional flash and batt in our climate zone.

Hybrid insulation systems are not always the right choice, but the hybrid system is ideal for some circumstances. By the end of this article, you will know:

• The benefits of hybrid insulation systems
• The drawbacks of hybrid insulation systems
• Whether or not a hybrid system is right for you

What Is A Hybrid Insulation System, Exactly?

At South Central Services, a hybrid system is two inches of closed cell spray foam paired with a batt of insulation. What makes our hybrid system different from traditional flash and batt insulation is the type and amount of spray foam used.

Our team only installs closed cell spray foam for hybrid systems. Between closed cell and open cell spray foam, only closed cell can create a vapor barrier. A vapor barrier is often necessary for exterior walls in our climate zone.

We also spray a minimum of two inches of closed cell foam. The vapor barrier of closed cell foam is only created after two inches of depth. If we sprayed any less, the vapor barrier would not be intact.

Pros Of Hybrid Insulation Systems

If you’re considering a hybrid insulation system, you’re likely trying to save some money. Spray foam insulation is expensive, so cutting costs with a layer of batt insulation can be appealing. Hybrid insulation systems can combine the benefits of closed cell foam and batt insulation.

There are two main pros of hybrid insulation systems.

1. Less expensive than spray foam insulation alone
2. Better sound control than spray foam insulation alone

Let’s examine the benefits of hybrid systems in more detail.

1. Hybrid Insulation Is Less Expensive Than Spray Foam Insulation Alone.

As you suspected, a hybrid system is less expensive than installing spray foam insulation. For example, if you wanted to insulate the exterior walls of your new build home, the cost per square foot would break down as follows:

• Closed cell spray foam: $3.50 to $7 per square foot
• Open cell spray foam: $2.63 to $4.13 per square foot
• Hybrid insulation system: $4.50 to 6.50 per square foot

Our highest rate for closed cell spray foam is $1.75 per board foot, meaning two inches of spray foam would cost $3.50 at most. Fiberglass batt insulation ranges from $1 to $3 per square foot, leaving the maximum cost of hybrid insulation at $6.50.

While this is a higher cost than open cell spray foam, open cell does not offer a vapor barrier. If your exterior walls need a vapor barrier based on your climate zone, your choices would be between closed cell and a hybrid system. Depending on how many inches of insulation your walls would need, a hybrid system is likely more affordable than closed cell foam alone.

2. Hybrid Insulation Has Better Sound Control Than Spray Foam Insulation Alone.

One great benefit of open cell spray foam is its sound attenuation abilities. The cellular structure of open cell spray foam allows it to absorb and muddle sounds. In exterior walls, this muffles neighborhood noise pollution. Sound attenuation does not eliminate sounds but makes noise quieter and indistinct.

Because of its cellular structure, closed cell spray foam offers a vapor barrier. However, it cannot absorb sound like open cell spray foam can.

When closed cell spray foam alone is installed in exterior walls, it offers a vapor barrier. However, closed cell foam cannot counteract neighborhood noise like open cell foam can.

In a hybrid system, adding a batt of insulation offers noise attenuation. Batt insulation, like fiberglass, has an internal structure that can muffle noise. When insulating your exterior walls with a hybrid system, you can benefit from the vapor barrier protection of closed cell foam and the sound attenuation properties of batt insulation.

Cons Of Hybrid Insulation Systems

While the additional inch of closed cell foam can solve many problems associated with traditional flash and batt insulation, hybrid insulation systems are still imperfect.

There are two main cons to hybrid insulation systems.

1. Potential for batt insulation to sag or gap
2. Limited application options

Let’s examine the top two issues related to hybrid insulation systems in more detail.

1. Batt Insulation In A Hybrid System Can Sag Or Gap.

Whenever batt insulation is installed, there is a risk of gapping or sagging. Gapping is a problem that occurs during installation. There can be gaps when insulation batts are not sized appropriately to the cavity they are filling.

Sagging is a problem with batt insulation that occurs over time. As years go by, batt insulation naturally starts to sag. There is nothing about the structure of a batt that is self-supporting.

An additional inch of closed cell spray foam does nothing to change the nature of batt insulation. However, one benefit of a hybrid system compared to batt insulation alone is the thermal barrier created by the spray foam.

If you opted for a hybrid system in your exterior walls and the fiberglass batts sagged after fifteen years, your building envelope would not necessarily be compromised. To meet building codes, we install two to four inches of closed cell spray foam in exterior walls. As few as two inches of closed cell could create the necessary R-value to insulate your walls.

While sagging is not ideal, it may not compromise the effectiveness of your thermal insulation in a hybrid system application.

2. Hybrid Insulation Is Mostly Limited To New Construction Applications.

You may have noticed that our only description of hybrid systems is exterior walls. Hybrid insulation systems have limited applications compared to closed cell or open cell spray foam alone.

The limited applications are partially due to the specific goals of a hybrid system. For example, you are not as concerned with sound control in your attic, so you would not have a hybrid insulation system installed in your attic floors or walls.

The other reason hybrid systems are so limited is the limitations of batt insulation. While closed cell spray foam is one of the most versatile insulations on the market, batt insulation cannot be installed below the ground. Below-grade applications like crawl spaces and basements cannot have hybrid insulation, even if the sound control would be beneficial. The batt insulation would absorb moisture and could cause mold problems.

Because hybrid systems are limited to exterior walls, this insulation method is also limited to new construction applications. Very few homeowners are willing to tear down their drywall to gain access to their walls for insulation. When a new home is being built, those areas are easy to access. For existing houses, however, hybrid systems are not a realistic option.

The Bottom Line About Hybrid Insulation Systems

South Central Services began installing hybrid insulation systems to give our customers a functional option compared to traditional flash and batt. Hybrid systems are an excellent method for combining high-performing spray foam with sound-controlling batt insulation. In some cases, a hybrid system can be more cost effective than spray foam insulation alone.

However, hybrid systems are designed for one purpose: insulating the exterior walls of a new construction building. Existing homes looking for insulation upgrades should consider something other than the hybrid system. Unless the existing home has been essentially gutted, a hybrid approach is not the insulation you need.

Now that you know the benefits and drawbacks of hybrid insulation, your next step is to:

• Discover the best way to insulate a new construction home
• Learn more about why new home insulation is so expensive
• Find out why homeowners trust South Central Services to insulate their new homes