How Deep Do Foundations Need To Be For A Garage Tips For Getting Your Garage Foundation Right

How Deep Do Foundations Need to be for a Garage? Tips for Getting Your Garage Foundation Right

Renovating a room or building a new garage into your home will require a lot of time and effort as you have to take a lot of factors into consideration. One of these factors is the foundation of the garage which will support the entire structure and prevent it from falling from its own weight.

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Foundations are necessary for a building as it’s supposed to transfer the entire load of the structure onto the surrounding soil. Every building is required to have these and each of them has its own different method of constructing their foundation.

Here we’re going to give you a necessary guide to understanding how deep you should go in order to build a strong foundation for your garage.


Check for the Type of Soil in the Area

Soil in the Area
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The first step into knowing how deep you need to go for building a foundation is to check the type of soil you’re going to build on. This is necessary as you need to understand how the soil reacts in various scenarios, especially on how it’s able to handle when a specific amount of load is built on it. 

Each type of soil has a different way of bearing a certain amount of load and the foundation needs to go deeper the less the topsoil can handle the weight. 

There are also particular soils that will react in certain ways with the various seasonal changes. Foundations need to go deeper to a certain point where the soil isn’t affected by and movement that’s occurring above the ground.

The Condition of the Ground

Mainly, the method of how a foundation is built is to take away the topsoil and use the undisturbed soil that’s below it. This means that you need to go down to a point where there is soil that hasn’t been used or backfilled yet to give strong support for your garage to be built on.

These soil compounds that you need to pass through are ones that have a lot of foreign objects in them which makes the soil loose. Another is an area of the soil where there have been drains installed.

You need to go as deep as possible in order to find an undisturbed area where the soil is still fully intact so you can lay a strong foundation on it.

Adjacent Structures Nearby

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Whenever you are going to start excavating to create a foundation for your garage, make sure that the foundation doesn’t compromise any adjacent structure nearby. A good way to do this is to go to the same depth as the foundation of the building nearby. 

If you’re creating a foundation that is close to another building then you should be careful when digging down. The problem with building to nearby structures is that there’s a tendency that the foundation will start to weaken. 

You should check your local laws or the proper limit of how close you can build a structure to one that’s nearby. Any chances of you building a structure too close to another want can severely weaken its foundation causing it to fail.

Watch Out for Trees

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Trees will have a huge influence on how deep you should build the foundation of your garage. They have a tendency to cause the soil that’s surrounding them to shrink as they tend to absorb the moisture from the ground. You need to check the type of soil that you’re planning to build on and how large the trees are surrounding it.

Most construction that occurs with trees nearby often digs deeper into undisturbed soil in order to prevent any damage which is caused by a weakened foundation.

Some soils like clay have a tendency to shrink more compared to other types of soil. The amount of water that’s been drawn out from it will also depend on how big the tree is.

Consider How the Load that the Foundation Can Carry

You need to understand that the foundation that you’re going to build will also depend on the size that you’re going to construct. It needs to be able to support the entire load of the garage in order to provide stable support to prevent it from easily breaking apart. 

Check the soil that you’re going to build on and ask a professional to tell you how deep you should build a foundation.

It’s also important to create a foundation that’s thick enough to remain stable. The width is necessary to maintain stability and strength whenever you’re building any type of structure.

Remember that you’re creating a large structure such as a garage that is going to contain your car and all of your storage items. As a building like this is hollow on the inside, the walls of the structure need to be strong in order to create stronger support for the entire room.

Drains and Sewers Nearby

The load of the building is going to be transferred throughout the entire foundation so it’s important that the base of your garage needs to be strong. 

This is why you should check the perimeter if there are any factors that may cause the foundation to weaken. Some of these factors may include drains and sewers.

Sewers and drainage leave a gap around the area which can heavily affect how the soil is going to support the weight of the entire garage. The affected area can cause the foundation to weaken and eventually crack from its own weight.

During excavation, it’s necessary that you should check for the nearest drain or sewer that’s around the place. If there is one, it’s a good idea to build the foundation on the same level as them.

What is the Purpose of Foundation?

  • It is the main reason behind the stability and durability of any structure. A stronger foundation means a more stable structure.
  • Avoids lateral movements of supporting materials.
  • If your foundation is proper, then it will distribute load into the surface of the bed evenly.
  • Provides level surface on the construction of substructure.


It’s important that you should never forget to build a strong foundation that will support your entire structure. One wrong move or an unstable build will cause the whole place to collapse which will create a huge problem and may even result in injury and damage.