Why Walls Are Thick?


Your walls do a lot more for you than set apart the inside of the building from the outside and separate different rooms. They have other functions like maintaining the temperature of the house and supporting the roof.

These and other reasons require them to be strong and thick. However, different types of walls serve different purposes so they are designed and built differently. Some of the ways that they vary are their thickness and the material used to make them.

Take a look at some of these walls, their thicknesses, and some more valuable information.

Why are walls thick?

Buildings are designed with thick walls for many reasons. Some are for the structural integrity of the house and some are just built so for the convenience of the house’s future occupants. Here is a couple of them:

  • Thick walls make the house feel safer, hence making the people living in it feel more secure from what is outside.
  • They also offer insulation from the elements. This is because they form a large barrier that makes it harder for cold air to travel into the room and warm air to travel out.
  • Thick walls create deep window sills. These are convenient storage points for your books, potted plants, or a coffee mug as you enjoy the natural light.
  • In the same way that they provide insulation, thick walls also make a good soundproof barrier, giving you a peaceful night and some privacy.

How is the thickness of a wall decided?

Here are some of the things that are considered when determining how thick the walls will be in a unit:

  • Climate: if the house is in an area with a cool to mild climate, then it must have thick walls, especially the exterior ones. This will ensure that they can hold plenty of insulation to retain warmth in the building. 
  • The material used to build the walls determines the thickness as well.
  • The number of floors. A tall building will have thicker walls to provide it with enough structural integrity.

How thick should walls be?

The wall’s thickness will also depend on what type of wall it is. Walls can be put into two categories- load-bearing and non-load-bearing walls.

  • Load-bearing walls are those that support the weight of the structure.  The weight is spread throughout the walls down to the foundation. These cannot be demolished because they will cause serious jeopardy to the structural integrity of the unit. 
  • Non-load-bearing walls do not support a floor above them or a roof. They do not offer any structural integrity and their main purpose is to divide units into partitions.

Let us take a look at some of the wall types together with their functions and the thickness that is required of them:

1. Load-bearing wall 

Like I had said earlier, these walls support the structure of the building. They can be further subdivided into:

  • Precast concrete walls. These are built by casting concrete in a wall mold and then curing it in a controlled environment. These walls should be between 4 and 12 inches thick to work optimally.
  • Retaining wall. These are walls that are designed specifically to resist pressure from the soil that is caused by liquid pressure, earth fills, and sand. They should be around   215 millimeters (8.4 inches) thick to be able to resist the pressure at different levels.
  • Masonry wall. These are walls constructed using bricks, concrete blocks, or stones.  The minimum thickness of a masonry load-bearing wall is 1 foot for a maximum wall height of 35 feet. After that point, the thickness will need to be increased b 4 inches for every extra 35 feet upwards.
  • Pre-panelized metal stud walls. These walls are used on the exterior of the building. The walls are panelized off-site and transported to the construction site. 
  • Engineering brick walls. These are built using the special engineering bricks that are used to offer more strength and resistance to buildings. The minimum thickness of these walls is 9 inches.
  • Stone wall. These are built from solid stone and they are strong, durable, and they look good.

With all these wall types, the thickness will increase concerning an increase in the building’s height. As a result, the stress exerted on the building’s foundation also increases, making the whole construction uneconomical.

2. Cavity walls

These walls are formed by constructing an outer wall and an inner one with some space between them and then they are fastened to each other. This cavity prevents rainwater from getting into the second wall. The cavity can also be filled to provide insulation for the house.

There are building regulations that dictate how thick cavity walls should be. It can be 265 mm (10.4 inches) to 275 mm (10.8 inches) thick. The inner wall and the outer one should be 4 inches thick and the space between them can be anywhere between 2 and 2.7 inches thick for buildings that have at most 2 stories.

If the building can be higher, the thickness also has to increase. The exterior leaf of the wall can be between 103 mm (4.05 inches) and 206 mm (8.1 inches) and the interior leaf maintains its dimensions as above. The cavity still retains its width of between 50 and 60 mm.

3. Partition walls

These are non-load-bearing walls and they are used, as the name suggests, to subdivide a large space into rooms and corridors. They usually only occupy one story so they could go from floor to ceiling or end midway.

There are different types of partition walls depending on the materials used to make them. Here are some of the most commonly used ones:

  • Brick partitions. They can be made out of either plain bricks, reinforced bricks, or bricks that are built in a framework made out of wood. They usually have a thickness of half a brick, which is 100 millimeters (3.9 inches).
  • Glass partitions. These are an affordable method of creating partitions in addition to being light and easy to put up. The glass wall can either be made of a single glass sheet with a wooden framework or from hollow glass blocks joined to each other. The standard thickness for a glass partition wall is 100 millimeters.
  • Concrete partition walls. These are made out of concrete slabs that are supported by vertical members. These can be cast in situ by pouring the concrete mix into intermediate columns with a thickness of around 100 mm. If the wall is constructed from prior cast slabs, its thickness is usually between 25 and 40 mm.

4. Shear walls

These are walls that are designed to reinforce the building’s structure by resisting forces like the wind and earthquakes. Like the other types of walls, these are also grouped by the material used to make them. Here are the most common types:

  • Concrete shear walls. In this wall, a concrete slab with reinforcement runs from the foundation to the top of the building. The thickness of this wall ranges between 150 mm and 400 mm.
  • Steel plate shear walls. A steel plate is bound by columns and floor beams.

5. Panel walls

These are non-load-bearing wall types. It is mostly used for decoration. They can be put directly on wall studs or they can be attached to a wall that has already been put up. There are various types of paneling depending on the layout of the panel itself:

  • Sheet paneling is brought about when the pane is made into one large piece that measures around 4 feet by 8 feet. This large panel can be fashioned out of plywood, fiberboard, and some hardwood trees.
  • Plank paneling is when a narrow piece of wood is hung next to another plank panel until the wall is complete.

The thickness of the panel wall is determined by the type of material used to manufacture it. Panels made from hardwood and plywood are usually ½ inches or ¾ inches thick. However, there are some exceptions, such as Medium Density Fiberboard, which is thinner than all the other paneling at ¼ inches thick.

There is also some hardwood panel variety that is thicker than the rest, given its origin. These panels can go up to an inch thick.

6. Faced walls

Faced walls have the facing and the backing made from two different materials which are then bonded to each other. This ensures that they both experience common action under the load.

7. Veneered walls

This type of wall is somewhat similar to faced walls. The facing and the backing are attached but not so strongly. The goal of this is to also ensure there is a common action under the load.

Veneered walls usually take the thickness of one brick wall. This is also called a Wythe.

Final thoughts

The architect and the engineers in charge of the house can carry out a survey and deem whether your house will need thin or thick walls. There are a couple of features that can be used to make this decision.

I hope this article has helped to give you some insight on what goes on when determining the thickness of the walls and some of the reasons why they are built that way.

Melanie Asiba

Melanie is an author. She enjoys traveling, reading and trying out new things. In addition to writing for Apartment ABC. Connect with her at [email protected]

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