The Ultimate Spray Foam Insulation Guide

Some problems do not have a single answer – and that’s the case of home insulation. With so many materials out there that you could use, some people need a little bit of guidance. The most popular solution for a lot of homeowners is spray polyurethane foam (SPF), but is spray foam insulation the best for you?

The truth is that each individual home improvement project comes with its own set of circumstances that require specific solutions. It’s important you understand the pros and cons of SPF before you decide what to do. As spray polyurethane foam has gained a lot of popularity in the past few decades (at least in North America), let’s see what it is and how it can meet your insulation needs.

Term definition

Whether you’re looking to insulate your home or your office building, spray polyurethane foam is known to resists heat transfer. SPF is a spray-applied plastic that forms a barrier for air sealing. It can be applied on roofs, attics, walls, basements, and around corners.

The foam is created at the site by mixing unique liquid components. Due to the fact that the liquids react very quickly on contact, they almost instantly create insulating foam. It is used to seal gaps and reduce the infiltration of unwanted air through seams, joints, and potential cracks.

Types of spray foam insulation

There are two different types of spray polyurethane foam insulation.

  1. Open-cell spray foam insulation, which is light-density insulation usually applied in wall cavities. Due to a significantly lower insulation value, open-cell insulation can be crushed in your hand.
  2. Closed-cell spray foam insulation, which is medium-density insulation. It offers complete air sealing due to the rigid formation. Even though closed cell foam is more efficient (higher R-value), it is also more costly to buy.

Both open-cell and closed-cell SPF are thermoset cellular plastics made of millions of small cells crushed together.

Popularity of spray foam insulation

Many reasons have caused SPF to become extremely popular in the U.S., even though it has not yet conquered the insulation market in Europe.

For once, spray foam has the highest potential of dealing with air leakages. Because it is sprayed directly onto the surface, it has a better chance of covering all the potential cavities and small holes.

It’s also better than many other insulation options because it can be used not only as thermal insulation, but also as an air barrier. SPF can be applied to both vertical and horizontal surfaces, helping you build a successful energy-efficient building.

While its popularity is undisputed in the U.S., SPF has yet to reach the majority of homes and buildings in Europe. As a result, those homeowners who do want a job well-done with their SPF insulation might have a problem when looking for installers.

Potential problems with SPF

With SPF – and other forms of insulation, for that matter – installation is a key factor. A lot of the problems with spray foam insulation result from poor installation. Read on for the dos and don’ts of SPF.

  • Make sure you mix the chemicals correctly. If not, the foam will start to pull away from the surface it was applied on. Also, poorly mixed chemicals may cause extra-strong odors and health problems.
  • Keep an eye on the installers. Don’t let them rush through the installation – that reduces the efficiency of the spray foam insulation because of the resulting gaps and holes.
  • Spray a thick enough layer of SPF or instruct the installers on exactly what you want.
  • Take the local climate into consideration. Temperature or humidity levels can interfere with the SPF’s efficiency. Also, read the manufacturer’s specifications for the best conditions.

Don’t forget – installation is key! It will make the difference between insulation that works and insulation that causes problems later on.

SPF’s impact on the environment

Even though it is more efficient that open-cell spray, closed-cell spray foam can have a highly negative impact on the environment. This type of spray foam insulation uses HFCs with high carbon dioxide content.

Some manufacturers claim to sell eco-friendly based on soy or castor. However, it’s just a marketing spoof that usually means nothing. SPF is a material that’s still very much based on fossil fuels – just like the majority of insulation options.

In cold climates, you may be required to apply a vapor retarder layer over drywall before insulating with open-cell spray foam.

Potential health risks

Certain mixes of chemicals have been reported as causing lingering odor. In turn, the strong fumes also caused health reactions in the occupants, especially during the installation phase.

Therefore, the Environmental Protection Agency has issued warnings about the potential health risks involved. EPA has started developing a standard to monitor the off-gassing potential of the relatively new SPF.

Installing insulation in your attic requires more than a weekend, a pair of shorts and a T-shirt. It is essential that anyone involved in insulating a home with SPF will follow the recommended health guidelines.

Cost of SPF and DIY kits

Open-cell spray foam insulation usually is $0.44 to $0.65 per board foot. Closed-cell spray foam, on the other hand, is about $0.70 to $1 per board foot. While you could consult a professional for the insulation of your home, you can also do your research.

Installing spray foam professionally costs $1,905 in average. What about DIY kits, however? There are various brands that can help you figure out how to t install spray foam insulation on your own:

It will cost you between $300 and $600 to cover 200 square feet with a spray foam insulation kit – about two to three kits. This will help you calculate how much you need to buy and how high the costs will rise overall.


Knowing about the pros and cons of SPF can help you be more aware about the consequences of the decision you will make. All insulation materials have both advantages and disadvantages. With SPF, however, you can gain great energy savings if installed correctly.

Do you have spray foam insulation in your home? What kind of energy savings have you seen ever since installation? Talk to us about your experience in the comments below.

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William E. Eubanks
 

I'm one of the main writers on the site; mostly dealing with environmental news and ways to live green. My goal is to educate others about this great planet, and the ways we can help to protect it.

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