Faced Or Unfaced Insulation: Which One To Use?

Insulating your home will increase your energy rating, keeping your building cool in summer and relatively hot in winter while also acting as a sound barrier. Therefore, selecting the correct type of insulation for your renovation or structure is of critical importance.

There are mainly two types of insulation: faced and unfaced. They serve different purposes and yield various benefits if used correctly. Therefore, it is crucial to understand the difference when you insulate multiple parts of your home.

Faced insulation comes with a vapor retarder sheet on one side which greatly minimizes the growth of moisture and mold building up. On the other hand, unfaced insulation does not come with a vapor retarder sheet which makes it vulnerable to moisture. 

Though several differences put them apart, both faced and unfaced insulation offer you the same purpose, which is to minimize heat energy conduction. There’s not a noticeable difference between their R-values as well. Moreover, both types are preferred by homeowners because of their various qualities. Another similarity between the two is that they don’t work well when compressed. Both faced and unfaced insulation must not be compressed to preserve R-value. Therefore, it’s essential to cut the perfect fit, regardless of which type you have for use. Let us now come to addressing the differences.

Difference between faced and unfaced insulation

Here is a table to give you a better idea of the key qualities of faced and unfaced insulation that set them apart:

Faced InsulationUnfaced Insulation
Includes a vapor retarderDoesn’t include a vapor retarder
Provides moisture resistanceDoesn’t provide moisture resistance
Applied in exterior walls and atticsApplied in interior walls and floors
Costs moreCosts less
Minimal sound resistanceBetter sound resistance
CombustibleNon-combustible
Easy to installRequires extra effort in installation
faced vs unfaced insulation: differences

Faced insulation

As you already know, faced insulation has an additional sheet of tin foil, vinyl, or Kraft paper on one side that prevents moisture from catching up to the material. In terms of application, faced insulation is typically used for exterior walls and attic ceilings that face the outside area. Since the insulation has one side with a vapor retarder sheet, the sheet should be facing outward. Faced insulation requires support to fit into place. Staples and wires are the two most common options for holding the insulation in its place. Due to faced insulation coming equipped with a vapor retarder, it costs slightly more than unfaced insulation.

Furthermore, faced insulation offers less sound resistance in comparison with its unfaced counterpart. It’s also combustible because of the sheet it comes with. Insulation can play a major role in the spread of a house fire. Unfortunately, the vapor retarder of faced insulation is not resistant to fire. This doesn’t mean, however, that one shouldn’t go for faced insulation because Proper application is key here. If you use faced insulation in the right place, it can do wonders for you. Lastly, the vapor retarder sheet helps faced insulation stay intact to a great extent, making it easier to handle and install.

Unfaced insulation

Unfaced insulation has no sheet or barrier to keep it safe from moisture and mold. However, this doesn’t mean that it’s lesser than faced insulation in terms of performance. Instead, it works great in places that are not directly exposed to tough weather conditions such as interior walls and floors. Once installed in these parts of the structure, unfaced insulation will perform best. This is because it’s meant to be installed in areas where there are no chances of moisture growth. It can also be of benefit if applied as a second layer of insulation next to faced insulation.

Since it’s simple insulation with no vapor retarder sheet, unfaced insulation costs a bit less. One of its major advantages is its non-combustibility. In the unlikely case of a house fire, you can expect unfaced insulation to perform as a barrier between the flames and your house. This can be considered a major plus point for insulation. Moving on to installation, unfaced insulation is indeed a bit difficult to handle. It’s not accompanied by a barrier so it’s fluffy and prone to damage. Not to mention the hassle of making it stay in place because friction isn’t enough to hold it.

Faced and Unfaced insulation: R-Value difference

Both faced and unfaced insulation bring the same R-value for every inch of insulation. There’s not much of a difference in terms of effectiveness. Note that we’re referring to heat insulation here and not moisture retention. However, since faced insulation has a vapor retarder sheet, it is not affected by moisture. On the other hand, unfaced insulation can face a decrease in R-value if moisture finds its way to the material. This is because moisture reduces the effectiveness of insulation. Other than the case of humidity building up, both types of insulation will provide the same R-value.

Do you need a vapor barrier with faced insulation?

Since faced insulation already comes with a sheet that protects it from wetness, it does not need a vapor barrier. As for unfaced insulation, it’s best to add a vapor barrier to it if you’re planning on installing it in a place where moisture might harm the insulation. You can either go for faced insulation that comes equipped with a vapor barrier, or you can opt for unfaced insulation and apply a vapor barrier of your own for protection against wetness. At the end of the day, it’s your decision and it varies according to your specific insulation needs.

The use of unfaced insulation is general and even recommended, but then a plastic vapor barrier is applied over the unfaced insulation as a suitable replacement for faced insulation.

However, the usual strategy that is followed is to use faced insulation in outer walls and unfaced insulation on inner walls and where there is only a slight temperature difference between an upper and lower room, like in an attic.

Price

The price of insulation is determined by the R-value of your home’s insulation, location, and demographic area and may range from $0.50 to $1.70 per square foot with installation. (Reference).

On average unfaced insulation will cost $0.10 to $1.25 less than faced installation to install. (Reference).

Insulations:faced vs unfaced

Where To Use Faced And Unfaced Insulation.

Unfaced insulation can be used anywhere to insulate two areas thermally and noisily. Faced insulation is used when two spaces need to be insulated from moisture in addition to heat and noise.

Faced insulation is best for outer walls, attic roofs, garages, bathrooms, and kitchen walls. Unfaced insulation is recommended on all inner walls and also as an additional layer of insulation over faced insulation.

Let me explain this in detail;

The Garage

Generally, you should use faced insulation in your garage, especially if you live in a cold, humid climate or a hot, humid climate.

Faced insulation will keep the garage warm and dry and prevent moisture from reaching the frame of your garage, where it can cause mildew and rot of the structure.

Local building codes can require the use of faced insulation in your area, and it is worthwhile to check on the regulations before installing insulation.

Before you start insulating your garage, it is imperative to eliminate water leaks in the walls and roof. Moisture trapped between your wall and the faced insulation will cause mold and rot of your structure,

When welding and doing other heat-generating work in your garage, it will be worthwhile to use insulation faced with vinyl sheeting. Kraft paper is very flammable, and welding might cause a fire if you don’t take care.

When applying the second layer of insulation, unfaced insulation is sufficient. Another layer of faced insulation might trap moisture between the two layers, and that will cause rot.

Insulating your garage will be beneficial if the garage is attached to the house or you spend lots of time working in the garage. 

It will be of extreme value to insulate your garage with faced insulation if your garage is below the house. Insulating your garage in this scenario will prevent cold air from entering the rooms above the garage.

Special attention should be paid to ensure that the garage door closes snugly onto the garage door sill to prevent gaps through which cold air can come in.

Double-sided reflective insulation can insulate roofs and keep the garage cooler in summer and hotter in winter. Using it on ducts also has advantages.

The basement or crawl space

Should you use faced or unfaced insulation in basement walls?

Faced insulation is what needs to be used in basements and crawl spaces to minimize heat loss and entry of moisture. Make sure the vapor barrier faces the warmer side of the room you insulate. For example, the kraft paper should face the inside of the basement or crawl space when insulating.

Basements and crawl spaces could be costing you unnecessary money. Soil, concrete, bricks, and cement conduct cold, and the cold air penetrate your house from the basement or crawl space.

Insulating your basement or crawl space and heating will lead to less hot air movement from the home to the basement or crawl space and make your home more energy-efficient.

Insulating a basement or crawl space can save you up to 20% on your energy bill, and that will add up to a savings of up to $200 per year. (Source).

Eliminating heat loss from your home can almost be canceled by insulating your basement or crawl space with faced insulation.

Before insulating the basement walls, it is a necessity to eliminate all water leaks or even just a wet wall. Wet walls or moisture leaks will cause the moisture to be trapped between the damp wall and kraft papers and cause mold to grow.

All water pipes and heating ducts must be insulated with unfaced insulation to minimize heat lost out of the home and prevent pipes from freezing.

Cavities around all electrical cables and pipes coming into the house should be insulated with strands of unfaced insulation and foam spray to keep cold air from entering the crawl space or basement.

The floor of a crawl space or basement should be covered with a 6mm polyurethane covering to prevent moisture and cold from entering. In low crawlspaces that are not used as storage space, polyurethane can be substituted with unfaced insulation.

Insulating The Attic

Faced insulation should be used to insulate the roof of the attic while unfaced insulation can be used to insulate the attic floor. Correctly installing both faced and unfaced installation in the attic will increase the energy efficiency of the home.

Insulating the attic will also protect your house against moisture, mold growth, infestations, and drafts in the home.

Starting with the inside of the roof, make sure that the paper layer of the insulation is facing the house as that will be the hottest of the two environments and will protect the structure against moisture from the heated home.

Insulating the attic floor with unfaced insulation will prevent hot air from moving into the lower rooms via the attic floor and keep the rooms hot.

Before any work is started on the inside of the roof, it is needed to ensure no water leaks and that the roof cladding and ventilation are up to standard.

Insulating the walls will require that the kraft paper side is inside facing the attic to prevent moisture from entering the structure.

The Interior Walls

Unfaced insulation is recommended on interior walls because there won’t be a significant temperature difference between the adjacent rooms.

The unfaced insulation in interior walls will limit air movement in the home and improve the home’s energy efficiency.

Faced insulation is not recommended on interior walls as it might trap moisture between the kraft paper (vapor retarder) and the structure of the house. For this reason, only unfaced insulation is recommended.

There is not a big difference between rooms in the same house, and therefore there will not be a moisture buildup that must be limited from entering the structure.

However, it might be different for a bathroom and kitchen where the best will be to use faced insulation with the kraft paper in the direction of the hotter and more moist room.

Unfaced insulation of inner walls will lead to more energy efficiency if there are rooms in the house that inhabitants do not always occupy. Another significant advantage of using unfaced insulation for interior walls is the soundproofing effect of insulation that will enhance privacy.

The Exterior Walls

Exterior walls should be insulated with faced insulation to prevent moisture from ruining the framework of the house. Faced insulation with the kraft paper on the inside should be used, and care should be taken that it fits snugly between the wooden framework of the house.

The kraft paper should be stapled either on the inside or on the face of the wooden structure.

Insulation must never be compacted and should fit snuggly around water pipes, heating ducts, and electrical cables to limit cold air from coming in and hot air from escaping.

Using unfaced insulation is another option as long as plastic sheeting is applied afterward as a vapor barrier stapled to the framework.

Insulating Rim Joists

Should you choose faced or unfaced insulation for rim joists?

Rim joists should be insulated with unfaced insulation as it is often the space between two rooms of similar temperatures. Such spaces have no chance of developing moisture, so unfaced insulation is preferred over faced insulation.

The Rim Joist is the most significant contributor to energy inefficiency in your home, and more cold air can come in through it than all the windows combined.

A Department of Energy study on older homes revealed that the older houses that had their Rim Joist properly sealed had an 11.4% reduction in energy loss. (Source)

The following video will aid you in understanding the influence of the rim joist on cold air coming in and loss of hot air while the importance of effectively sealing the Rim Joist is explained.

The primary sealing of the Rim Joist with foam or foam board and hand sprayed foam is essential, but after that, the sealing of the space between floor joists with unfaced insulation is just as important.

Because you are insulating a space between two rooms of similar temperatures, you will use unfaced insulation.

Various sealing methods are available, including the insulation of the area where the sill plate covers the concrete up to the space between the floor joist.

While insulation methods vary from expandable foam to pieces of rigid foam insulation rimmed with hand-sprayed foam, the last touch will be done with unfaced insulation.

Conclusion

Faced and unfaced insulation play different roles in the insulation of a house and must be applied correctly to limit heat loss, sound, and vapor transfer. Faced insulation used with the vapor barrier facing the wrong way can lead to moisture trapped, leading to mold growth and rot of the home’s wooden structure.

Both faced and unfaced insulation has their unique advantages in controlling heat loss, vapor movement, and soundproofing of your home, and they should be used appropriately.

Charles John

Experienced HVAC technician with 8 years of experience in the industry. Capable of handling all sorts of heating and cooling equipment as well as proficient in operational management, construction-related techniques such as preventative maintenance, electrical troubleshooting and AutoCAD

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