Does a Garage Need A Cavity Wall?

Most often, people’s garages in their homes are cold, sometimes damp, and not temperature controlled. But with technology and standards changing, the preference for a more warm and comfortable space for cars and laundry units has increased. But what kind of walls make these conditions work, and do you need them? A cavity wall certainly comes to mind. 

A cavity wall is not needed for a garage but is certainly recommended for anyone trying to keep the climate in optimal conditions. The way that the cavity wall is set up ensure that no moisture or dampness makes it’s way inside. 

With the way that garages are exposed to so much climate, especially in colder environments, cavity walls have a dual lining to protect the house from everything that is trying to creep in from the outside. 

What is a Cavity Wall?

A cavity wall is a dual lined wall with a hollow space inside between them. The two walls on the outside of the hollow space are referred to as skins. Most often than not, the walls are made out of masonry material such as cinderblock or brick. This is because these materials absorb dampness and water slowly into the walls and out of the air. 

Dual Masonry Walls

When both the walls are made out of masonry material, it is more likely that the job will be done effectively. This is known as double wythe masonry wall. The purpose is not only to double proof the walls with water-absorbing material but also to connect them via metal wiring. It acts as insulation like interior walls. 

The Cavity

The function of the cavity is to drain water that is absorbed through the walls through what is referred to as the weep holes. The holes typically are found at the bottom of the walls or above the windows in order to protect windows from being damaged from rain or water, causing them to rot and need replacing. 

Why Have a Cavity Wall?

Cavity walls were introduced back in the 19th century of Europe. This makes sense because a lot of homes back then were built our of brick, which is why you see a lot of colonial brick homes in the States have cavity walls already built into them.  They are typically important for coastal climates as rain and water find their way into homes much easier in these areas. 

Cavity walls have major advantages to them, such as the basics keeping things insulted, weather-resistant, etc. but also they have other functions that with a little research one would be grateful for. 

As with anything, there are its downsides, and one should be aware of the shortcomings that come along with it. For example, redoing cavity walls themselves after corrosion is an incredibly difficult thing to do that most people would rather not bother with. 

Let’s take a closer look at both sides. 


Below are the main advantages one can expect when installing or already having a cavity wall in one’s garage. 

  • Little to No Chance of Moisture Traveling into Home
  • Temperature Control
  • Economically Cheaper
  • Easier Instal 

Effectiveness of Moisture Control

Cavity walls leave almost no room for any dampness or moisture to creep inside from the exterior wall past the interior wall leading into the home or garage. This is a certainty when you deal with the dual masonry walls. Because of the materials ability to absorb wetness and the thickness of the material, water simply can not go past. This can not be said for insulated walls that consist of plaster and drywall or even wood. 

Temperature Control

The space between the walls does not act as a conductor for the heat, and neither does the masonry materials. This being said, that means that heat from the exterior such will not make its way into the garage or house. It also can keep cool air or hot air in making it a wall that allows for temperature control on both sides. 

Easier Install

By adding an exterior wall to make a cavity wall, it usually involves little to no disruption of the house and can be a relatively easy job. This isn’t the case for everyone but is generally of what can be expected, all while maintaining the thickness of the wall as it’s not necessary to make changes to the existing wall if not needed. 


While a cavity wall is a great option is does have it’s downfalls like what happens when it needs to replaced, and what does that look like? Below are the main things to worry about when dealing with a cavity wall. 

  • A Bad Job – What Does It Lead To?
  • Corrosion
  • Thermal Bridging Issues

Poor Install

A poor install can lead to more harm than good in the first place. If there is wetness and moisture coming in from the interior walls of the garage, then that means something has seriously gone wrong. One thing to point to is the possibility of air pockets meaning that the masonry has holes, and its job can’t be done efficiently at all. Finding a well-experienced masonry company is important to avoid issues like these. 


While a cavity wall is meant to last a good amount of time, there are corrosion problems that occur after constant exposure to elements. This is especially in coastal towns when constant rain, wind, and sand penetrates the house making corrosion rates go faster. To fix corrosion is a lot more complicated than installing a secondary wall. Depending on the area that would need replacing, sometimes it is just easier to redo the entire thing. 

Thermal Bridging Issues

Thermal bridging is when an area is not seemed up properly and results in a loss of heat or the inability to keep cold in. It can be an install issue or a corrosion issue. It often looks like cracking in one specific area that is constantly breaking down. This is not uncommon with cavity walls, but luckily can be fixed by being patched up or glazed over initially. 

Comparing Garage Walls

Garages aren’t always as warm and fuzzy as the indoor environment of your household, and that’s because simply the things inside them don’t need to be at a comfortable temperature. So what do other people use for walls in a garage, and why? Is it as or more effective? Let’s find out. 

Type  DescriptionPros/Cons
Cavity WallThe one we are familiar with as it is two walls with an empty space known as the cavity in between—at least one of the walls being built out of masonry materials. Efficient with the cost of install. If installed properly, great way to keep damp and wetness out while retaining temperature inside. Corrosion occurs and can be difficult to fix depending on the issue, I.E., air pockets. This results in a total redo. 
Solid Singular Brick WallAs simple as it sounds, some homes just work with the brick wall from the outside as well as it being the interior wall as well for garages. Simple not suitable for weather resistance as you may find dampness in your garage, as well as cold temperatures, are often present on the inside. 
Party Walls These are shared walls within a garage of a townhome or multifamily unit. Depending on whether your building is a part of an HOA, then one may have no choice as to what their walls will be. Most likely, there will be some weather-resistant components to it.  

Final Thoughts

A cavity wall is certainly not necessary with today’s ability to install interior and exterior installation. However, it is recommended as it has a lot of benefits for a better price than other methods. While it may be an old school way of doing things, it has been tried and tested and rarely fails. 

Cavity walls seem to be the best option when it comes to garage efficiency with protection from the weather elements.  For those who care about the inside climate of their garage, this is the way to go.