What Is The Thickness Of Exterior Walls?
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Many factors contribute to the thickness of exterior walls, including facing materials, sheetrock, and additional layers. Building codes in various areas can dictate a minimum thickness, but there is no maximum thickness for exterior walls.
Most homes have wood framing featuring 2 x 4 studs, sheeting, and siding of choice, like stucco or vinyl or wood siding. Most exterior walls will range from 5 ½ inches to 12 inches, with certain brick walls ranging from 14 to 18 inches. Two-story homes usually have 2 x 6 or even 2 x 8 framing, creating thicker walls than a single story.
Another factor to consider is the type of insulation and any other additional layers present. The vast differences in these components are why there is such a wide range for the thickness of exterior walls.
What Are The Layers Of A Wall?
The various layers of a wall will determine its ultimate thickness. Typically, going from the inside of the wall to the outside, you’ll have between 4 and 5 layers of materials. Starting on the interior, these layers are sheetrock, the stud wall, weather barrier, sheathing, and siding.
Within these layers, you might also have additional wood supports for connecting various layers. Also, insulation can be present, but it typically would go between the wall studs, whether spray foam or batting. Therefore, it would not add additional thickness to the wall.
Here is a closer look at each layer of a wall to give you a better picture of the overall thickness.
1. Sheetrock Thickness
Sheetrock, or drywall, most commonly comes in ¼-inch, ½-inch, and ⅝-inch thicknesses. The standard thickness for interior walls is ½-inch sheetrock, whereas ¼-inch drywall usually lays over an existing surface.
Sometimes thicker drywall is needed for a particular reason, such as a fire rating or a shared wall between townhouses. In situations like this, builders will often use ⅝-inch drywall.
2. Stud Wall Thickness
The rough thickness of your exterior wall is determined by the size of your stud wall or wood framing. However, this by no means puts a cap on your exterior wall thickness. You can add a multitude of layers and siding options that increase the depth.
For example, the rough width of an exterior wall, just based on the wood framing, is usually 3 ½ inches. This is because many single-story homes use 2 x 4s in the framing.
But, the actual width of a 2 x 4 is 3 ½ inches. The 2 x 4 connotation is simply the nominal dimension based on the rough cut of wood. Once a 2 x 4 makes its way through the finishing process, a quarter-inch gets chopped from each side.
The result is a board that is actually 1 ½ x 3 ½. The same rule applies to all framing, whether you use 2 x 4, 2 x 6, or something else.
Using Larger Boards In Your Framing
If you have a two-story house or higher, it’s likely your home has 2 x 6 wood framing to add more stability. A 2 x 6 frame would bring your stud wall thickness from 3 ½ inches to 5 ½ inches. Some single-story homes also use 2 x 6 framing; it has benefits and drawbacks.
You can increase the energy efficiency of your home since you can fit more insulation between the studs. However, keep in mind, the thicker the studs, the more cost involved; plus, they’re heavier, so labor is more intense.
Actual Size Of Wood Framing
|Nominal Measurement||Actual Measurement|
|2 x 4||1 ½ x 3 ½|
|2 x 6||1 ½ x 5 ½|
|2 x 8||1 ½ x 7 ¼|
|2 x 10||1 ½ x 9 ¼|
3. Sheeting Or House Wrap
When you use wood framing and certain other materials, it’s essential to protect appropriately against moisture. Utilizing a house wrap, like Tyvek🄬, protects against moisture and its ill effects, like warping, buckling, mold, and rotting. You might also use some other type of plastic sheeting or barrier.
A weather barrier helps your framing and walls air out and breathe, in a manner of speaking. Although it doesn’t add significantly to the wall’s overall thickness, it’s still worth mentioning since it’s often included in the layers.
4. Sheathing Thickness
You can use various materials for sheathing in new home builds, and depending on your choice, it can serve several purposes. Primarily, sheathing provides an extra layer of stability to your exterior walls and a surface to attach siding to.
However, some types of sheathing can also offer added insulation and protection from environmental factors. Some of the most common sheathing materials are oriented-strand board (OSB), plywood, fiberboard, and foam board.
OSB is typically a minimum of 5/16 of an inch for studs that are on 16-inch centers. If the studs are on 24-inch centers, ⅜-inch OSB is better to add more structural support. But, the majority of homes use 16-inch centers to ensure proper stability and durability.
Plywood typically adds a ½ inch to the wall’s thickness, as does fiberboard, and typical foam board thicknesses are 1 and 2 inches. When it comes to choosing the suitable sheathing for your home, you need to consider cost, climate, moisture, and other factors.
Some types of sheathing will work better in certain environments than others.
5. Siding Thickness
The siding is what gives your home its aesthetic appeal and personality. You can choose from wood siding, vinyl, bright or muted colors, stucco, brick, and more. Except for brick, most siding options will add similar thicknesses to your exterior walls.
Typically, cladding adds anywhere from ¼ of an inch to ¾ of an inch, with some materials reaching closer to one inch. Keep in mind; this doesn’t necessarily mean the siding itself is this thick, but rather how much it extends after application.
So, depending on the installation method, some siding will only add its own thickness, while others will add more. Consider how vinyl siding angles out slightly, and you install it in an overlapping manner.
Also, for example, you usually apply stucco in three to four layers depending on the supports. Therefore, the finished product can be anywhere from ⅜ to ⅞ inches thick.
If you opt for a more specific siding, like log-look siding, you can add about 1.5 to 2 inches to your exterior wall. Brick adds considerable thickness, easily pushing your walls over 14 inches thick.
Therefore, the choice of siding will plays a significant role in your wall’s overall thickness.
Determining Exterior Wall Thickness
Since there’s no set exterior wall thickness, the only way to determine it is to add the individual components. So, if using vinyl siding, rigid foam sheathing, and 2 x 4 studs, you’d get about 5 ½ inches thickness.
If you’re installing log-looking siding over plywood sheathing and 2 x 6 framing, you’d get about 8 inches thickness. Opting for brick over plywood and 2 x 6 framing would get you about 15 inches of exterior wall thickness.
How Thick Are Exterior Brick Walls?
Brick walls are often considerably thicker than other wall types. Usually, you’ll have at least 4 inches of thickness added with a brick if using it as siding. This is when one layer of bricks is laid horizontally.
But, in many applications, a double-horizontal row is used, with the next layer being vertically-placed bricks. Building the wall this way adds 9 inches of thickness, but this can increase depending on how you lay the bricks.
For example, in one row, if you place one brick perpendicular to another, you’ll get roughly 13 to 14 inches of thickness. So, if one brick as siding adds 4 inches, your overall wall could be up to 12 inches thick. If using more rows of bricks, your wall could be 14 to 16 inches thick or more.
How Thick Are Concrete Walls?
Another option for exterior walls is using concrete walls. Standard concrete walls are about 6 inches thick. However, areas with high winds usually need at least 8 inches. Insulated concrete form (ICF) walls typically have a standard thickness of 12 inches.
Can Exterior Walls Be Too Thick?
Undoubtedly, thicker exterior walls can increase energy efficiency, stability, and features like added storage inside walls. However, thick walls also come with some drawbacks that you should consider.
Thicker walls take up more of your interior space, reducing your square footage. Another possibility is thicker walls might have trouble getting rid of internal moisture.
You could also struggle to get the desired amount of light into your home because of where the windows sit in the wall. This can potentially make your home feel almost cave-like and darker than you would like.
Once you are aware of these potential disadvantages, you can plan to combat them. For example, choose an effective form of sheathing or insulation that encourages moisture to pass from inside to outside with no hiccups.
Also, plan for the reduced interior space and either increase your footprint or design for smaller rooms. Of course, if you add to the overall size, you’re also drastically increasing your budget.
Other things to consider are aesthetics, adding additional lighting, and how to fit things like windows and doors into the walls. When you recognize all of these ups and downs, much of your choice hinges on personal preference.
Frequently Asked Questions
How thick are interior walls?
For an interior wall, the size of the framing will pretty much dictate the overall thickness. You have the drywall and the frame to consider. Most interior walls use ½-inch thick drywall, and a piece usually goes on either side of the framing.
Therefore, most interior walls are 4 to 4 ½ inches thick. If using 2 x 6 framing, interior walls would be 6 to 6 ½ inches thick. In some areas, like bathrooms, ⅝-inch drywall is used, bumping up the overall wall thickness slightly.
What are the primary functions of an exterior wall?
Exterior walls add protection, strength, and insulating properties to your home. They support the roof and overall structure, as well as help with moisture and air exchange between the exterior and interior. They also serve as noise barriers, keeping sounds both in and out of your house.
How thick are the walls in a tiny house?
Including the interior walls, sheathing, framing, and siding, a tiny house wall is typically 4 ¾ to 5 ½ inches thick. If you plan to transport your tiny house, you’ll likely look to keep your walls closer to the minimum thickness. This way, you can maintain the lightest load possible without sacrificing support.