Is Flash And Batt Insulation Worth It?

You've done your research on flash and batt insulation. You know that this insulation method attempts to marry the performance of spray foam and the budget-friendliness of fiberglass batts. You've weighed the pros and cons of flash and batt, but you still aren't sure it's the right choice for your project.

South Central Services has insulated hundreds of homes with spray foam insulation. We do not install traditional flash and batt insulation because there are better insulation options in our climate zone. However, what is most important is that you are informed and able to make a decision that you feel confident about. This article will analyze flash and batt and what it can realistically offer you as an insulation method.

By the end of this article, you will know:

• How flash and batt compares to fiberglass batts
• How flash and batt compares to spray foam insulation
• How flash and batt compares to dense pack cellulose
• A realistic ROI for flash and batt insulation

Don't have time to read right now? Check out everything you need to know at a glance.

Is Flash And Batt More Affordable Than Other Insulations?

The best way to determine whether flash and batt insulation is worth investing in is to compare it to your other options. Will the flash and batt method save you money? Or are there other less expensive insulations available?

Let's compare flash and batt prices to three popular forms of insulation: fiberglass batts, spray foam, and dense pack cellulose.

Fiberglass Batt Prices

Fiberglass batts are one of the least expensive insulation products. Depending on the size, R-value, and facings of a fiberglass batt, the cost per square foot could be as little as $0.60 or as much as $3. Fiberglass batts will cost an average of $2 per square foot in an exterior wall.

Spray Foam Insulation Prices

Spray foam insulation is one of the most expensive insulation options. The cost per square foot varies depending on the application and how much insulation should be installed.

The average price per square foot to insulate an exterior wall would fall in the following ranges.

• Closed cell spray foam: $2.90 to $5.80
• Open cell spray foam: $1.75 to $2.75

Dense Pack Cellulose Prices

Dense pack cellulose ranges from $1.60 to $2.50 per square foot. The average cost per square foot for exterior wall applications is approximately $2.05. However, the cost per square foot will vary depending on the contractor you work with. South Central Services does not offer dense pack cellulose.

Be aware as you research cellulose pricing that blown-in cellulose and dense pack cellulose are two different types of insulation. Blown-in cellulose is not installed in walls, and the pricing for blown-in may not be an accurate representation of the dense pack method.

Flash And Batt Prices

Traditional flash and batt uses one inch of closed cell spray foam, costing approximately $1.45 per square foot. Adding the fiberglass batt cost of about $2 per square foot, the total cost per square foot would be between $3.15 and $3.75.

We do not recommend traditional flash and batt because too little closed cell spray foam is installed, which can result in condensation between the layers of insulation. In northern climates like Pennsylvania, vapor barriers are vital to protect homes from extreme weather conditions. Closed cell spray foam can only create a vapor barrier at two inches. Another inch of closed cell would raise the cost per square foot by an additional $1.15 to $1.45. However, this increase is necessary for the wall insulation to be functional long-term.

Is Flash And Batt Easier To Install Compared To Other Insulations?

If flash and batt insulation isn't more affordable than other insulation methods, does it offer different benefits? If you opt for flash and batt for your exterior walls, will it be an easier installation process?

Let's compare the installation requirements for flash and batt, dense pack cellulose, fiberglass batts, and spray foam.

Fiberglass Batt Installation Requirements

Fiberglass batts are a common insulating material that any insulation contractor can install. Fiberglass is also available for homeowners to purchase and install themselves. For homeowners who install fiberglass, investing in personal protective equipment (PPE) is a must. No matter who is installing the fiberglass, batts must be fitted to the exact size of a cavity for optimal performance.

Spray Foam Insulation Installation Requirements

Spray foam insulation should be installed by professional contractors. Depending on the insulated area, a project could take one to four days. For exterior walls, insulating can usually occur within two days. When the professionals arrive to spray, residents and pets are required to vacate for their safety.

Spray foam insulation is also technically available as a DIY. However, we do not recommend DIY spray foam for exterior walls. The goal of a DIY is to achieve a comparable result at a lower investment cost. The cost of materials is the same whether you hire a professional or insulate the space yourself. However, DIY insulation results are not insured if something goes wrong, and have a high chance of netting poor end results.

Dense Pack Cellulose Installation Requirements

Dense pack cellulose insulation should be installed by a qualified professional contractor, but can technically be a DIY insulation. The DIY-friendliness of dense pack cellulose is limited by both rental equipment and installation complexity.

Dense pack insulation is not a fool-proof product. Installers must know how to install dense pack correctly and must use the correct equipment. Rental machines for blown-in cellulose are unable to handle dense packing.

If you choose dense pack cellulose for your exterior walls, we recommend working with a professional contractor. Filling the wall cavity is vital and not intuitive to the average homeowner. Working with a trained contractor will ensure the best results from professional equipment.

Flash And Batt Installation Requirements

Flash and batt should only be installed by a professional contractor. Technically, a homeowner can purchase DIY spray foam kits and fiberglass batts at a home improvement store. However, installing flash and batt with no complications would be incredibly difficult for a homeowner.

Both the spray foam and fiberglass insulations must be installed correctly to maintain the highest possible level of performance. Not every spray foam contractor installs flash and batt insulation. An effective installation will require finding a willing, reliable, and knowledgeable contractor. Be sure to work with a professional who understands the building science related to your climate zone. In our climate zone, Climate Zone 5, the traditional flash and batt method will not yield reliable results, no matter who installs the insulation.

Does Flash And Batt Perform Better Than Other Insulations?

Since flash and batt insulation can only be installed by a professional contractor, you want to make sure that the performance is worth the investment. Compared to your other insulation options, will flash and batt deliver good results and last the lifetime of your home?

Let's compare performance and longevity for fiberglass batts, dense pack cellulose, spray foam, and flash and batt.

Fiberglass Batt Performance

Unfortunately, fiberglass batts are not a high-performing insulation. Fiberglass R-values vary by batt, but improper installation can damage a batt's performance. Batts must completely fill a cavity with no gaps to offer their advertised R-value.

In perfect conditions, fiberglass batts should last nearly 100 years. In real-life applications, fiberglass should be checked every 15 to 20 years for damages, especially if installed in an area with high moisture content.

Spray Foam Performance

Spray foam insulation is a permanent solution. Spray foam does not shrink, sag, or settle over time. The performance of spray foam also remains the same as the insulation ages. Ultraviolet rays are the only thing that can break down spray foam insulation, so spray foam should last indefinitely if not exposed to sunlight. Unless your home faces a disaster like a fire or flood, there is no need to check on the performance of your spray foam.

Spray foam has a high R-value as well as air-sealing capabilities. Spray foam is a permanent solution that offers excellent and consistent performance.

Dense Pack Cellulose Performance

Dense pack cellulose is an insulation product that settles over time if not installed correctly. In exterior walls, cellulose could settle and leave the top portions of walls uninsulated. As long as cellulose is packed into the wall cavity correctly, it should last for decades. You would only need to worry about replacement in the case of a fire or flood.

Cellulose appropriately packed is a heavy and dense insulation that offers better performance than fiberglass. The R-value of cellulose depends on how much is installed and how it is installed.

Flash And Batt Performance

In theory, traditional flash and batt insulation has a slightly higher performance than fiberglass batts alone. The addition of spray foam adds approximately R-7 to the overall R-value of the insulation system. However, the inch of spray foam insulation cannot provide a vapor barrier. At best, the spray foam creates an airtight seal, which fiberglass cannot supply on its own.

Flash and batt should be checked for damages every 15 to 20 years, especially if problems like cold spots, draftiness, or odors are present.

The fiberglass portion of flash and batt may sag or settle over time. If your flash and batt experiences a condensation problem, costly repairs and mold remediation will result.

Since condensation is a serious concern for homes in our climate zone, 2 inches of closed cell spray foam should be the minimum. Otherwise, the performance of traditional flash and batt will deteriorate.

What Kind Of ROI Can You Expect From Flash And Batt Insulation?

The ROI that you can expect from traditional flash and batt insulation will depend on the climate zone you live in. Let’s examine potential ROI based on your weather patterns.

Flash And Batt ROI In Southern Climates

Let's say you chose the right contractor who is comfortable installing flash and batt insulation. The contractor knew the risk factors of your climate zone and how to mitigate them. Because you live in a southern climate and chose the right contractor, you can enjoy all the benefits of flash and batt with none of the problems. What kind of ROI are you looking at?

Flash and batt insulation will offer better performance than fiberglass batts alone. For the additional cost of closed cell spray foam, your home's energy efficiency will be boosted. You can expect to save more on your energy bills than if you had just insulated with fiberglass batts.

Flash And Batt ROI In Northern Climates

For any homeowner in a northern climate like Pennsylvania, traditional flash and batt insulation will not offer a meaningful ROI.

Building science tells us that vapor travels through the air and condenses in colder air. The more extreme temperature differences between inside and outside of your home, the more necessary a vapor barrier becomes.

With our distinct four seasons, our exterior walls should have a vapor barrier. Traditional flash and batt does not provide this feature.

While an inch of spray foam insulation will increase energy efficiency performance in theory, the practical application leaves your home open to mildew, mold, and hefty remediation costs.

It is not worth saving a few thousand dollars if you are vulnerable to repairs that will cost tens of thousands.

Which Has A Better ROI: Flash And Batt Insulation Or Spray Foam?

The performance of flash and batt will still not compare to insulating with spray foam. Your energy savings would be less than what you would have saved on each bill with spray foam.

Even in a perfect scenario, flash and batt cannot surpass the benefits of spray foam insulation alone.

We recommend considering another option for your exterior walls, such as closed cell spray foam, open cell spray foam, or dense pack cellulose. These methods have fewer risks, and some cost approximately as much as flash and batt.

Is Flash And Batt Insulation Right For You?

Our team at South Central Services does not recommend this insulation method for our climate zone. Our weather patterns are too extreme for 1 inch of closed cell spray foam to be effective. For readers in a southern climate with more mild weather, this traditional method may be feasible. If so, find a contractor in your area who can explain the building science behind the method.

If you live in a northern climate and are interested in the flash and batt method, we strongly recommend that you get a minimum of two inches of closed cell spray foam. At South Central Services, we call this a hybrid method. Increasing the amount of spray foam will increase the investment cost, but prevents maintenance and replacement costs down the road.

Now that you've compared traditional flash and batt insulation to other insulation options, your next step is to:

• Discover the best way to insulate a brand new home in Pennsylvania
• Weigh the pros and cons of the hybrid insulation method, a version of flash and batt
• Compare the best insulations for new construction houses