Can Spray Foam Insulation be Left Exposed?

Interior of new home room under construction. The interior of a new home room under construction showing studs and insulation.

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Spray Foam Insulation is used to insulate the house and keep unwanted substances from entering, like insects and mold. It can only be left exposed in certain areas of the home.

Spray Foam Insulation can not be left exposed if it is in the common living areas of the home. It needs to be covered with a thermal barrier to prevent the start of a fire. Places in the home where spray foam can be exposed include the attic and crawl space.

Continue reading to learn why spray foam insulation cannot be left exposed.

By the way – before we get too far along here, if you want to connect with other homeowners and builders and get more great ideas for your home to make your space the best join my free private Facebook group, Remodel Reality here.

What is Spray Foam?

Spray foam is a substance sprayed on the inside frame of houses for the purpose of insulation. It is a newer type of insulation, now being installed on most houses whether they are new or being renovated. Since the substance starts out as liquid and drys to be solid, it can get into the cracks that regular insulation cannot. It is either enough insulation on its own, or then covered with the normal pink fiberglass insulation that we all know and love. However, fiberglass is not as effective as spray foam. It is not able to keep the temperature at a constant degree and increases the price of energy bills. (Source)

Spray foam is much more costly, but also more cost-effective. It not only insulates the home much more effectively but can keep out unwanted substances, like insects and mold. It is able to get into the cracks that fiberglass insulation cannot, sealing all unknown cracks in the framing of the house. If applied correctly, the spray foam can act as a noise barrier for the home as well. Applying spray foam insulation in your home will be much worth it. (Source)

Can Spray Foam be Exposed

Since spray foam is sprayed onto the wall as a liquid, and drys as a solid, many homeowners wonder if it can be left exposed.

Sprayfoam cannot be left exposed, due to its ability to easily catch on fire. The material is very flammable and needs to be protected from high heat in the home.

If a home is up to code, the spray foam needs to be covered in the common living areas of the home, even the basement. Even though the basement may not be commonly used, it is still seen as a living space.

There are a few exceptions to this rule.

The attic and crawlspace within the home can usually be left exposed since it is rare that inhabitants of the home occupy them.

Spray foam also needs to be covered if it is on the outside of the home. It needs to be protected from outside substances that can deteriorate and ruin the quality of the spray foam insulation. If you aren’t sure if an area of spray foam needs to be covered, check with the home codes rules and regulations. (Source)

Thermal Barriers

Spray foam insulation needs to be covered with some form of a thermal barrier. The thermal barrier is known as the layer between the spray foam and the inside of the house. The thermal barrier will reduce the risk of fire and protect the living space. Thermal Barriers can be either a spray or material that is put over the spray foam insulation.

The most common kind of thermal barrier is drywall. In order to be up to code, the drywall must be at least 1/2 an inch thick to prevent the start of a fire.

Drywall is a material placed over the spray foam. Other kinds of thermal barriers are plywood and gypsum. (Source) The thermal barrier must be a 15-minute thermal barrier, which means that it can prevent the spray foam from catching on fire for 15 minutes when once exposed to high amounts of heat. (Source)

Another reason to cover the spray foam is that its quality is damaged when exposed to light and UV rays. Covering the spray foam with a thermal barrier will keep the spray foam from deteriorating and losing value. (Source)

How to Apply Spray Foam

Spray Foam Insulation is usually done by the house building company, but if you choose to do it yourself, make sure to follow the rules. Being exposed to fresh spray foam can be very dangerous. There are special conditions for when it needs to be sprayed as well. There is proper gear to wear during the spray foam installation process. Wear a respirator for your lungs, goggles for your eyes, gloves for your hands, a suit for your body, and make sure to wear shoes that you don’t necessarily care about if they get ruined by the spray foam.

Never spray the spray foam on a wet surface, or else it won’t stick to the wall. The moisture level should be okay as long as the surface has been dry for a few weeks. It is rare that the moisture level will be too high, but it needs to be at 20% or below.

There are many different types of kits, so make sure to get one that is the right size for the job. Some application machines require the use of two or more people and are very heavy. If you are applying it by yourself, make sure to get a kit that you can handle on your own. Make sure to cover all areas of the room that you do not want sprayed, like doors or windows. Since this insulation is a spray, it’s hard to control exactly where it goes. You can do this by stapling plastic around the edges.

When it comes to the actual application, spray the edges first, and then everything else. Only spray it about 2 inches thick at a time, and wait two minutes in between for it to dry. Make sure to spray all of the edges and cracks, but do not spray over the pipes, spray underneath or behind them. Once you are done spraying, you can cover it with fiberglass insulation for extra protection of your home. (Source) Do not forget the thermal barrier, as spray foam cannot be exposed in the common living areas of the home.

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Rob Orr

Me and my family have lived through a nightmare of a remodeling project gone wrong, making countless mistakes including placing trust in the wrong hands. Despite these setbacks, we took matters into our own hands for many aspects of the remodel, ensuring quality workmanship guided by expert advice. Through my personal experiences, I've created My mission is not only to share the pitfalls we encountered but also the successes we achieved by combining our efforts with trusted professionals. By sharing both the highs and lows of our journey, I aim to help others navigate their own remodeling projects with greater confidence, ensuring they benefit from our lessons learned.

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