Faced vs. Unfaced Insulation in Your Garage


When I insulated my garage, one of the first decisions I had to make was between faced vs. unfaced garage insulation.

Although it was easy to tell the difference between them, I had no idea which I should use. So I did some research to find the differences to help make my decision. Each has it’s pros and cons, but depending on your situation, it might not be an obvious choice.

Generally, you should use faced insulation for your garage, especially if you live in a very cold or humid climate. Using faced insulation may help you comply with your local building codes. However, if your garage already has a layer of insulation, use unfaced insulation. 

In this article, we will explain what faced insulation is, why you might want it, and whether it is better than unfaced insulation for your garage. 

What Is Faced Insulation? 

Faced insulation is insulation that includes a vapor barrier to guard against excessive moisture.

The barrier on faced insulation is usually made out of Kraft paper, and it is sometimes called a vapor retarder. It helps prevent moisture from moving from one space to another, and it usually faces the inside of the room

By contrast, unfaced insulation is plain insulation that doesn’t have a vapor retarder.

Usually, when you are insulating a room or house for the first time, you will use a vapor retarder. However, facing is not good for second-time insulation applications. 

When to Use Faced Insulation

In this section, we will go through the various situations you might want to use faced insulation in. We will also explain some of the benefits of using faced insulation as opposed to unfaced insulation. 

You Live In a Cold or Rainy Climate

If you live up North with really harsh winters, you might want to consider getting faced insulation.

This is because the moisture in snow, ice, and rain can lead to mold and mildew. Faced insulation will help keep the garage warm during the winter and help prevent moisture from getting in and ruining the frame of your wall. 

Additionally, if you plan on converting your garage into an office, gym, or bedroom, it’s worth getting faced insulation. It’ll help keep your garage dry and warm. 

You Live In a Hot and Humid Climate

On the flip side, if you live in a hot and humid climate, faced insulation can help fight mold and mildew.  

Many areas have a mix of hot and cold climates with both cold, harsh winters and hot, humid summers. If that sounds like where you live, that’s an extra reason to use faced insulation. 

Your Local Codes Require It

Depending on your local building codes, you may be required to install a vapor barrier when building your house. If that is the case, you should get faced insulation so that you fulfill those requirements. Every place is different, so look up the local building codes in your county. 

It’s important to note that using Kraft paper is not the only way to create a vapor barrier. There are quite a few ways to create vapor barriers, as explained later. However, it is an affordable, easy way to do so. 

You Don’t Yet Have Insulation

As I mentioned earlier, faced insulation is generally used on first-time applications.

Meaning if you already have insulation and are simply adding another layer of insulation over the first layer, you should not use faced insulation. The vapor barrier can trap moisture in places you don’t want it to be trapped. 

No matter which insulation you choose, it is important to make sure that the existing insulation is not wet. If it is and you’re looking to add new insulation to fix the moisture problem, you would be better off searching for the root cause of that moisture. Do you need to fix a leak and waterproof your garage walls first?  

When Not to Use Faced Insulation

Although faced insulation should generally be used when insulating your garage for the first time, there are a few cases where you don’t want to use it.  

Keep in mind that all this is not taking local building codes into account. If you are required to install a vapor barrier, you must comply with all local laws. It’s always a good idea to check with your local building planners to see if you need a permit for your garage project.  

You Have Existing Insulation

Don’t add faced insulation over existing insulation. If you have an insulated garage and are adding more insulation over an existing layer, use unfaced insulation. 

You Work With Heat or Fire

One of the problems with faced insulation like Kraft paper is that it can be extremely flammable. Usually, this isn’t a problem for garages.

However, if you plan on using a lot of heat or fire in your garage next to your walls, this can pose a problem. 

Faced Vs. Unfaced Insulation in Your Garage

For example, if you plan on using your garage for your welding projects, you run the risk of having a welding fire. If you do use faced insulation, you must take extra precautions to avoid having a fire. You may be required to cover the Kraft paper with other materials, depending on your local codes. 

Here is a video about when you may want to use faced insulation and when you may not want to:

Types of Faced Insulation

If you will be using faced insulation, what kind of faced insulation should you use? What are your options? 

Kraft Paper

Kraft Paper is an insulating barrier that is made of thin but strong cardboard. This cardboard is made from wood pulp. Although Kraft paper itself is not a good insulator (indeed, it is often used for paper shopping bags which can easily get wet), it can be turned into an excellent insulator when soaked in transformer varnish. 

Aluminum Foil

Some moisture barriers are made out of aluminum. An aluminum foil vapor barrier is great for thermal insulation as well.

Paper

Paper can also be used to provide a vapor barrier. 

Vapor Barriers vs. Vapor Retarders

Is there a difference between a vapor barrier and a vapor retarder? Or are they the same? 

These terms are often used interchangeably. As mentioned earlier in this article, a vapor barrier is often referred to as a vapor retarder. However, they are not the same thing.

A vapor barrier is basically “a type of vapor retarder with a permeance rating of 0.01 perms.” Perms are short for permeability, which is a rating system used to determine how effective a vapor retarder is at stopping moisture from getting through. The more moisture that can permeate the material, the lower the rating is going to be. 

There are many technicalities involved in this rating, which is not the focus of this article. Here is a good article that discusses permeability ratings and the differences between vapor barriers and vapor retardants in depth. 

Installing a Vapor Barrier Correctly

Whether you use Kraft paper or aluminum foil for your facing, you must make sure that it is not damaged. Often, when a facing is not effective, it is because it was not installed correctly, not because the material itself was not effective. For example, aluminum foil can easily get torn, especially when installing sockets in the wall. 

If you don’t know how to install faced insulation yourself, it is best to get a professional to do it for you so that it is effective and long-lasting. 

Conclusion

For most people who are insulating their garages, faced insulation is the better option. Remember to check your local building codes to find out if you need a vapor barrier. If you don’t know how to install a facing, get a professional to help.

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