What You Need to Know About DIY Spray Foam Insulation Kits (2023)

Whenever the summer season kicks in, we must ensure our homes are properly insulated to keep the cold draft outside so our loved ones stay toasty.

Some people are bent on doing it themselves with a Spray Foam Kit they buy at Home Depot or Lowes. But, frankly, any professional sprayer would advise against the kit and against renting a high-pressure foam rig to try and DIY.

What You Need to Know About DIY Spray Foam Insulation Kits (1)

And Professionals advise against it, not because they want to earn money. Instead, they say it should not be done because: spraying foam is like running a chemistry lab at home.

It is very serious stuff. And if you make a mistake, it could make your home unlivable.

Where can you DIY with foam kits?

Spray foam insulation kits may provide a solution for a quick do-it-yourself project at home, like insulating a small wine cellar that is too small for a company to take on. Or a single wall cavity that had been opened up, you could use a kit on that.

Or if you have new construction and they are doing batt insulation, you could spray the penetrations and seams inside before the batt insulation goes in. Then, you block the airflow (convective heat), and the batt installer stops the conductive heat transfer.

But, for those who want to understand Foam Kits for DIY, here is what you need to know.

Before opting for spray foam insulation kits, let’s take a deep dive to unearth what you might need to know. With this knowledge, you can make the right choice that adds value to your home.

What are spray foam insulation kits?

Outdoor temperature variations can drastically affect any home—wall, attic, and crawlspace insulation work by guarding against the effects of the changing seasonal environment.

Similarly, spray foam kits help keep the air indoors from escaping or outside air from breaching your home. In so doing, spray foam protects against extreme cold or heat while also attempting to keep out pesky critters.

Let’s talk R-value

Insulation material is usually labeled as R, followed by a number from 1 to 60. What does such labeling denote? For starters, R stands for the resistance a specific material offers against heat transfer. For instance, during winter, a high R-value prevents cold drafts from entering your home, keeping your haven warm.

The walls should guard against heat transfer in hotter months by keeping your interior space cool. As such, a higher R-value implies greater resistance to heat transfer.

But what you need to understand is Prescriptive Code requirements vs. Performance code. I’ve written an entire article about it on my Stellrr website.

The bottom line is that the prescriptive code requirement in Austin is R-49 in the attic. Prescriptive means the R-value as the code was written for blown insulation.

While the performance code means the R-value required on a product to meet or exceed the written prescriptive code. So in Austin, the performance code is R-25 in the attic. Spray foam insulation is measured by the performance code, not prescriptive.

How is spray foam at least twice as effective as the prescriptive code for blown fiberglass/cellulose/rock wool?

For starters, spray foam is the only solution that blocks all three types of heat:

  1. Radiant
  2. Convective
  3. Conductive

Whereas blown insulation stops conductive heat only.

Next, spray foam takes your attic ductwork outside the building envelope (in a 130-degree attic). Finally, foaming the underside of the roof brings the attic ductwork inside the building envelope.

We call this a semi-conditioned attic. And now your HVAC unit is in an environment that makes air duct leakage irrelevant. And the attic is 5-10 degrees warmer than the inside of your home, meaning your ductwork can maintain the air temperature much better.

So when that 55-degree air comes out of the air handler in the HVAC system, it runs through a 75 – 85-degree attic (not 130 degrees).

That means that the room at the far end, away from your air handler, can receive 55-degree air instead of running through “reheating lines” in a traditional attic.

There are 13 crucial steps to properly cleansing your attic from where it is to transform it into a space-age style attic (think NASA space ships foam insulation). First, how do you manage the humidity after the HVAC isn’t running as much, which means it is not pulling as much moisture out of the air? How do you solve that (and nobody is addressing this besides Stellrr)?

I won’t publicly go through the 13 steps because I don’t want my competitors to sound competent and totally botch the work we specialize in (retrofits on existing homes). However, we discuss the 13 steps during our Diagnostic Consults when reviewing potential projects.

What is another downside of DIY foam kits?

Foam Kits and high-pressure foam rigs (like we use) start in two separate containers. Like in chemistry class, when the two meet, they react, growing 30 times. And during that reaction, it puts off a vapor.

So you would be directly exposing yourself to that chemical reaction. Our installers wear Moon Suits, full-face respirators with supplied fresh air. You have to have the proper PPE.

The foam becomes inert (harmless) within a minute, and as soon as the vapors settle, you are good. Depending on the foam brand, you could wait 72 hours to re-enter the space. Or if you use a super green foam like we do, with proper ventilation, people can re-enter the area in as soon as 4 hours. But most foams are 48 hours.

How much foam do you need in a Kit?

It is pretty simple. Foam is measured by the board foot. So imagine a piece of plywood that is one inch thick. Now cut that plywood into a 12”x12” piece. That is one board foot. 1”x12”x12”.

So to spray a closed cell (R-6.7 per inch) kit in a wall cavity, you would need two board feet (R-13 Austin performance code). Two board feet per one square foot of wall space. So to properly insulate a wall to an R-13 closed cell, you need 21 board feet of material (16” wide, 8’ tall, 2” thick). The open cell requires more board feet because the R-value is closer to R-3.9 per inch. But nearly all DIY kits are closed-cell foam.

The DIY kits generally come in 100 bd ft up to 300 bd ft kits. So you could do five wall cavities 16” on center by 8’ tall. And the cost per board foot in the DIY kits is about the same price per board foot that a professional company would charge. So there aren’t significant savings in DIY.

Moreover, a 100 bd ft kit will have a lower yield. In a perfect test environment with a professional sprayer, the kit may achieve 100 bd ft. But in the real world, it could be as bad as 60 bd ft up to 90 bd ft at best.

A DIY kit can be as large as a small propane tank (2-4 gallons), whereas we use two 55-gallon drums and usually carry 4-6 drums in the rig with us to do a house (220-330 gallons).

What type of Personal Protective Equipment must you wear?

Personal safety is critical when working with chemicals. Invest in the right gear to undertake such a DIY project. For example, foam spatter can be difficult to scrape off once it cures, and we’re sure you don’t want it on you once the action begins. Some of the protective equipment you need include:

  • A full-face respirator ($195) with the proper filters. Or a fresh air respirator ($3,000-$7,000) as we have.
  • Disposable coveralls because the foam will get on you as it reacts and sticks. If you get an unprocessed A-side (one of the two parts) on you, it sticks like superglue to your skin. That is why we wear MoonSuits.
  • Chemical-resistant gloves. Again unprocessed material and curing foam will get on you, guaranteed. So be prepared.

It would be best if you also protected the objects in the area where you are working. For example, grab some tape and plastic to cover windows and places to which you don’t want the foam to be misted or stuck.

Next, you’ll need a ducted fan to suck/blow out the building vapor from the chemistry reaction.

You will need several spare “guns” or “tips” because the kits will clog up quickly without an auto-cleaning mechanism. With our guns ($3,000 ea), we have air blowing out of the gun at all times, which cleans off the tip and helps prevent the material from crossing over (which means we have to clean (hours) and rebuild the gun with new o-rings ($100 o-ring kit each rebuild).

Fortunately, the DIY guns are much cheaper ($150 each), and you may only go through 1-2 per DIY kit.

Can foam be sprayed onto a wet surface?

It is common for crawlspace wood (floor decking and support joists) to be most from the moisture wicking up into your house from the dirt.

Foam will not correctly adhere to surfaces that exceed 18 percent moisture content. You can buy a moisture meter online for less than $50.

We prefer that the wood is in the 5 to 14 percent moisture content range. So wait until the substrate (surface) dries up before installing.

How easy is it to install foam with a DIY kit?

Let’s say that practice makes perfect. A new sprayer will take a year of spraying foam daily before they are decent at it. So I would not expect a good outcome from a DIY project. But it may be your only option.

If the space you need spraying is below a company’s minimum, consider what other area you’d like sprayed and have them do it too.

The bottom line is this: DIY spray foam kits are a fine concept. But it is a product that should not be on the market. Frankly, installing foam should be regulated by the Texas Department of Licensing. But anybody can call themselves a professional with no basis for the claim.

Here is what to do next!

You are welcome to call Stellrr at512-520-0044today for a free estimate! In addition, you can claim yourHome Energy Audit, Thermal Mapping, and Blower Door Test($297 Value FREE). Or download our e-book:(A $27 Value)! So you can make an informed and intelligent decision when hiring an insulation contractor near you! I’ll link our website in the comments for you.

Stellrr Insulation & Spray Foam,

401 Congress Ave, #1540 Austin TX 78701,


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What You Need to Know About DIY Spray Foam Insulation Kits (2)


Are DIY spray foam kits worth it? ›

The short answer is, “NO!” While some smaller projects like insulating the corners of doors and windows with DIY foam may seem doable for experienced crafters, anything involving spray foam insulation is better left to those who are properly trained.

Can you buy spray foam insulation and do it yourself? ›

DIY Spray Foam Pros

The small areas around doors and windows are great small projects for DIY foam insulation. The experienced homeowner could avoid a contractor's minimum charge by doing these small spaces themselves. You can buy the kit at your local home improvement store and get the job done on your own time.

How many square feet does a DIY spray foam kit cover? ›

DIY Spray foam kits come in different sizes ranging from as little as 20 board feet (20 sq. ft. @ 1″) on the low-end up to 1200 board feet (1200 sq. ft.

Is spray foam a good business to start? ›

With the right pricing structure and a steady flow of client acquisition, a spray foam insulation business can be very lucrative, and you can generally cover your investments quickly if you do approach the process correctly. The spray foam jobs typically expect 50% in gross profits and about 25% in net profits.

What are the negatives of spray foam? ›

The Downsides of Using Spray Foam Insulation in Homes
  • It Can Lead to Mold. Spray foam insulation mold problems are quite common. ...
  • It Can Have a Foul Odor. Spray foam insulation is mixed on the job site, and improper ratios of chemicals are common. ...
  • It Can Lead to Termite Damage. ...
  • It's Too Airtight.
Nov 30, 2022

How many square feet does a 55 gallon drum of spray foam do? ›

½# Open Cell Spray Foam 55 gallon kits: 16,000-21,000 board feet coverage We also have Open Cell Spray foam insulation for your project. Open cell is great for sound, and you will get your air barrier at 3.5” thickness.

How thick should spray foam insulation be? ›

For closed cell spray foam, you'll want to make sure that your foam is 2-3 inches thick on the walls and 4-5 inches thick on the roof deck. For open-cell foam, the same thickness is needed for the walls, but the roof deck should be sprayed to be 6-10 inches thick.

Does insulation need a vapor barrier? ›

Vapor barriers—sheets of plastic or kraft paper—keep water vapor out of the wall cavity, so the insulation stays dry. Not every type of insulation needs a vapor barrier. But if it does, the barrier should face inside in northern, heating climates, and outside in humid southern climates.

Is 3 inches of spray foam enough? ›

When using closed-cell foam in walls, it is generally considered sufficient when 2 to 3 inches are sprayed. Open-cell foam in walls would not be sufficient with just 2 inches, requiring at least 3.

How far does 1 can of spray foam go? ›

Each can covers approximately 25 Board Feet. Spray-foam insulation is a quick and easy way to seal the gaps in your home and save on energy costs. While many foams require mixing two components out of large canisters, Seal Spray Foam can be applied directly by simply attaching a spray nozzle to the can.

What is the profit margin on spray foam? ›

Sprayfoam applications are very profitable if priced right and installed efficiently. It is very important to get the right training and support upfront to ensure long term viability of a new SPF contracting company. Gross profits of 50% and net profits of 25% or greater are expected.

How long does it take for spray foam to pay for itself? ›

In many cases, people who install spray foam in their homes can expect to see an average ROI between 3 to 7 years depending on the size of the building, where the home is located, the condition of the HVAC unit, home energy usage and the areas being spray foamed.

Is spray foam worth the money? ›

Spray foam insulation is worth it – in fact, depending on the type of insulation you currently have (or don't have), spray foam insulation could save you up to 50% on your energy bills. Its highly effective heat retention means you simply don't need to use as much energy to heat your home.

What is better than spray foam insulation? ›

Advantages of Blown-In

Since it's blown in, it can fill small gaps and hard-to-reach areas, like spray foam. It's available in fiberglass, the most commonly used insulation material. It's more cost-effective than spray foam and (depending on the material used) can fulfill a wider range of applications.

Does spray foam decrease home value? ›

In fact, when done correctly and professionally, spray foam insulation can actually increase the value of your home. This type of insulation adds value to any residential property by providing superior energy efficiency, durability, soundproofing capabilities, and more.

Is spray foam a fire hazard? ›

Like many materials found in a home or building, spray foam can ignite and burn if exposed to a sufficient heat source. Foam insulation should be considered combustible and handled accordingly.

Will spray foam stop water? ›

Spray foam insulation is the only type of insulation that will stop the moisture outside from coming in. Fiberglass insulation and other products don't provide enough of a barrier. You'll have gaps that will allow dampness to come inside. Many of these other insulations can even absorb moisture.

What's the difference between closed cell and open cell foam insulation? ›

Open cell foam is full of cells that aren't completely encapsulated. In other words, the cells are deliberatly left open. This makes the foam a softer, more flexable material. Closed cell foam is made up of cells that are, as the name suggests, completely closed.

How many spray foam kits do I need? ›

To determine how much foam you'll need, you need to know 2 things, the area to be insulated (square feet) and how thick you want your insulation (inches). Multiply both of these together and you get the number of board feet of insulation that you need to buy.

What is better spray foam or cellulose? ›

Regarding r-value, there is a tie between both the insulation materials. The R-value of cellulose is 3.6-3.8 per inch, while for spray foam, it is 3.5-3.7. Generally speaking, NEEECO recommends cellulose insulation over spray foam insulation for retrofit construction (existing homes).

What is the R-value of 2 inch thick spray foam? ›

R-Value In 2 Inches Of Spray Foam

The R-value ranges from R-3.5 to R-3.6 per inch. The filling of a 2×4 cavity yields about an R-13.

Do you have to drywall over spray foam insulation? ›

Because any type of spray foam is combustible, along with most other building materials, we need to protect the wall from the foam. By installing gypsum board over the foam, we have protection on the inside of the building for a life-saving purpose.

When should you not use spray foam insulation? ›

Spray foam insulation of any type should not be applied to a substrate or in an air temperature above 120 degrees Fahrenheit. In storage, you also want to keep your spray foam insulation at least 3 inches from any heat source.

Can I sleep in my house after spray foam insulation? ›

According to the EPA, occupants must stay away from the building while it cures (and as long as the dust remains) for at least 24 to 72 hours, something they, devastatingly, are not always told. If the spray foam continues to off-gas, the building can be inhospitable to occupants for years.

What is the lifespan of spray foam insulation? ›

Both types of spray foam insulation can last anywhere from 80 years to 100 years, with closed cell spray foam having a slight edge in terms of durability. For most families, this represents the lifetime of the house and then some!

Which side faces out on insulation? ›

Picking the right face is essential with fiberglass insulation that has a vapor barrier (meaning with Kraft paper or foil attached on one side). It should always face the warm-in-winter side. Thus, in cold climates, it should face the interior; in hot humid climates, it should face the exterior.

Should you put plastic between insulation and drywall? ›

After the insulation is in place you will want to add a vapor retarder, sometimes called a vapor barrier, if you need one. Not every wall does. A vapor retarder is a material used to prevent water vapor from diffusing into the wall, ceiling or floor during the cold winter.

Do I need to install vapor barrier with spray insulation foam? ›

A vapour barrier is not necessary with closed-cell foam but with open-cell spray foam such as Icynene®, it is sometimes required. Any air that migrates though a building envelope will carry water vapour. As Icynene® spray foam creates a seamless air-seal, it controls air leakage and the moisture in the air.

What is the R-value of 2x4 spray foam walls? ›

They are available in widths suited to standard spacings of wall studs and attic or floor joists: 2x4 walls can hold R-13 or R-15 batts; 2x6 walls can have R-19 or R-21 products. Loose-fill insulation—usually made of fiberglass, rock wool, or cellulose—comes in shreds, granules, or nodules.

What is the highest R-value for a 2x4 wall? ›

Fiberglass and rock wool batts—2x4 walls can hold R-13 or R-15 batts; 2x6 walls can have R-19 or R-21 products. Generally, batt insulation is the least expensive wall insulation material but requires careful installation for effective performance (see page 4).

What is the R-value of 4 inches of spray foam? ›

Closed cell spray foam has an R-value of R-7 per inch. In comparison, open cell spray foam has an R-value of R-3.8 per inch.

Does spray foam crack over time? ›

Spray foam is rigid and inflexible once it cures, and foam boards are rigid from the outset. So when these materials expand and contract because of temperature changes - and that's when, not if - they can crack.

How long to wait between coats of spray foam? ›

Concerning efficiency, spray foam has historically had one minor weakness: it often needs to be installed in passes (layers) that require approximately 30 minutes of wait time between each pass to allow the foam to sufficiently cool.

What can I use instead of spray foam DIY? ›

A List of Foam Alternatives
  1. Fiberglass batts;
  2. Rock wool batts;.
  3. Blown-in fiberglass or cellulose, manufactured from recycled paper and similar products.
  4. Recycled cotton (denim), normally used for soundproofing but also provides R-13 thermal insulation.
Mar 16, 2022

Can you spray foam over electrical wires? ›

While there may be debate between individual contractors about spraying foam insulation over electrical wires, industry guidelines state that spray foam insulation can be applied directly over electrical wiring.

What do you seal spray foam with? ›

Seal Spray Foam Butyl Rubber Sealant

Our Butyl Rubber Sealant has excellent adhesion to a wide range of substrates. Once cured, it takes on durable plastic qualities with “self-healing” behavior.

What item has the highest profit margin? ›

Beauty products such as makeup, skincare, fragrance, nail supplies, and wellness products are some of the highest margin products available. With so many suppliers and manufacturers, you'll be sure to find a great wholesale price and the items themselves are often easy to display and market to customers.

How much is spray foam market? ›

The average cost of spray foam insulation is $6,080, with costs typically ranging between $3,385 and $10,960. The price per board foot is $0.45 – $0.75 for open-cell spray foam and $1.00 – $1.60 for closed-cell spray foam insulation.

How much spray foam is too much? ›

If the foam is sprayed thicker than recommended for its type, excessive heat can result causing odors, cracks, shrinkage, or charring. To prevent this, never spray more than a 2” thickness at a time. To spray more than 2”, apply in layers allowing the foam to cure for at least 15 minutes between layers.

What are the disadvantages of spray foam insulation? ›

The Downsides of Using Spray Foam Insulation in Homes
  • It Can Lead to Mold. Spray foam insulation mold problems are quite common. ...
  • It Can Have a Foul Odor. Spray foam insulation is mixed on the job site, and improper ratios of chemicals are common. ...
  • It Can Lead to Termite Damage. ...
  • It's Too Airtight.
Nov 30, 2022

Can I spray foam myself? ›

The answer is yes, but drywall needs to be removed before you can install the foam. Spray foam expands rapidly when it is applied to the inside of walls.

Is open cell spray foam better than fiberglass? ›

Closed-cell spray foam has an R-value of roughly 6.5 per inch while open-cell spray foam has an R-value of 3.5 per inch. The R-value of fiberglass is significantly lower at around 2.2 per inch. In addition, fiberglass insulation loses R-value over time while spray foam insulation maintains its effectiveness.

Is it better to DIY spray foam insulation or professional? ›

With spray foam insulation, the work has to be done right for best results. There is no benefit to saving money if the job is half done. And there no benefit if the DIY work takes twice the time of an experienced contractor. Hiring a professional is by far the best option for long-term success.

Should you spray foam yourself? ›

If you're thinking about buying a do-it-yourself spray foam insulation kits for your home, fire officials and those in the industry recommend you think again because of safety and fire issues. Spray foam acts as a great insulator and vapour barrier, but it's made up of chemicals and needs to be handled with care.

Can you do injection foam yourself? ›

The material forms a barrier to heat transfer and air leaks. Installing injection foam requires a professional. It's the most expensive way to insulate your home.

What's the difference between injection foam and spray foam insulation? ›

Although both forms of insulation are open-cell, they do not operate the same way. Spray foam is sprayed onto the material it will insulate and then expands as it dries in order to create more insulation between two materials. Injection foam is injected onto the material to insulate and does not expand.

How much of a difference does spray foam insulation make? ›

One of the most significant advantages of spray foam insulation is that it is a better insulator than other types, meaning homeowners can save money on their heating and cooling bills. Closed-cell foam insulation is a powerful insulator with an R-value (thermal resistance) of 6 to 7 per inch of thickness.

Is 2 inches of spray foam enough? ›

2 inches of spray foam is enough in particular situations while using a particular type of foam, but it is not a universally accepted standard for sufficiency. When using closed-cell foam in walls, it is generally considered sufficient when 2 to 3 inches are sprayed.

Can I sleep in my house after spray foam? ›

Typically, however, it is recommended that you avoid long-term exposure to this indoor environment for at least 24 hours after spray foam has been installed to let the curing of the chemical building agent occur in the environment.

Do you need drywall over spray foam? ›

Because any type of spray foam is combustible, along with most other building materials, we need to protect the wall from the foam. By installing gypsum board over the foam, we have protection on the inside of the building for a life-saving purpose.

How many years does spray foam last? ›

Both types of spray foam insulation can last anywhere from 80 years to 100 years, with closed cell spray foam having a slight edge in terms of durability. For most families, this represents the lifetime of the house and then some!

How long do you have to stay out of the house after spray foam? ›

Of course, spray foam can be unsafe for occupants too. According to the EPA, occupants must stay away from the building while it cures (and as long as the dust remains) for at least 24 to 72 hours, something they, devastatingly, are not always told.

Where not to use expanding foam? ›

Avoid using the foam near any ceiling lights or heating appliances. If you spray the foam near a ceiling light, for example, there is a chance that it could catch fire due to the flammable nature of the spray. Additionally, it could also cause damage to the light itself if it cures around any wiring.

Can spray foam be left exposed? ›

The quick answer is yes and no, because spray foam can be left exposed in some areas of the home with others require a thermal barrier according to the code. If the area of the home that has been sprayed with foam is directly connected to the living space, then it has to be separated by a thermal barrier.

Does spray foam insulation help with soundproofing? ›

Spray foam is known as one of the best types of insulation to install to reduce noise. One reason why spray foam is considered the best in noise reduction is because it not only blocks out unwanted noise but keeps in good noise. When watching a movie, for instance, you want the sounds to be kept within that room.


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