How to Build a Tunnel from House to Garage?

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When we were kids, we all wanted a secret tunnel connecting our house to the garage. If you still wish to fulfill your childhood dream, you’re in the right place. 

Usually, people build a tunnel in their house for emergencies. Besides, building and designing a tunnel is a lot of fun. However, you must remember that underground engineering requires more special attention than regular structures.

You don’t want to build a tunnel that will harm your life, right? 

So, how to build a tunnel from the house to the garage? Here is the complete guideline for building an underground tunnel between the house and garage.

How to Build a Tunnel from House to Garage

How to Build a Tunnel from House to Garage: Complete Guidelines

Before jumping into the main topic, I want to remind you that building a tunnel in your house connecting your garage isn’t child’s play. Unless you have years of experience in tunnel engineering, you should hire a professional architect and construction team for this project.

Before digging the soil for the underground tunnel, you must have mineral rights to that land. Besides, you should call the utility company to mark the lines to prevent future disputes.

1.  Take Necessary Engineering Measures

Don’t just dig randomly and try building an underground tunnel. It requires precise underground engineering and design. A little bit of carelessness can cause severe damage to your property and your life.

Many people think that stable-looking soil or dirt is as safe as a well-built underground tunnel. If you solely rely on the soil for the ceiling, at some point, your underground tunnel will collapse and injure people.

Again, many people assume that installing a series of culvert piping or shipping containers will be enough to hold the weight. But when you use thin metal or structure to hold the underground soil, your underground tunnel will collapse.

That’s why before digging for the underground tunnel, consult an underground engineer and plan accordingly.

While building an underground tunnel between the house and garage, you’ll have to pay special attention to the air circulation.

While designing an underground tunnel, you should create a path for free airflow. Besides, to keep the air inside the tunnel clean, you’ll have to regularly do tunnel maintenance tasks like oiling the door hinges.

Moreover, you’ll have to do regular pest control to keep your underground tunnel free from pests and insects.

2.  Design Blueprint

Having a blueprint is necessary while constructing an underground tunnel connecting your garage and house.

While designing the blueprint for your underground garage tunnel, you have two options. One, you can build a tunnel that will be under the surface entirely. Or, you can have a cut and cover the underground garage tunnel.

If you opt for the cut and cover tunnel, you’ll have to plan how you’re going to cover the tunnel. Besides, compared to the other tunnel design, the cut and cover tunnel is more exposed.

However, if you’re a novice to underground tunnel construction, building a cut and cover tunnel will be easier for you.

But if you want to construct a tunnel that will be under the surface completely, you’ll have to design and implement it accurately because a little mistake in this type of tunnel can be fatal. Moreover, this type of tunnel requires additional ventilation and electrical lines.

Again, while building this type of underground garage tunnel, you’ll have to consider the materials used and make sure they don’t cause a fire.

If you want to use flames for lighting in the tunnel, you should never use wood-paneled walls. For lighting the tunnel, it’s advised to use regular LED lights.

3.  Flooring & Roofing

During the process, you’ll have to decide how you are going to do your tunnel flooring and roofing. If you plan to use cement for your tunnel flooring, you must reinforce the cement with rebar. However, if you want to give your garage tunnel a medieval look, you can leave the tunnel floor as it is.

After deciding what to do with your tunnel floor, you’ll require a solid design and structure for your tunnel roof. While designing the tunnel roof, you’ll have to include ventilation in the design.

Without proper tunnel ventilation, the air will become stagnant and hazardous. Besides, due to lack of ventilation, molds will start to grow inside the tunnel, which will make the situation even worse.

While designing the tunnel roof and floor, you’ll need a design for the subterranean walls. When designing the subterranean walls, you’ll have to follow the local city building guidelines.

As the tunnel walls are going to hold tons of dirt and rock, it has to be well built and designed. Otherwise, your tunnel wall will collapse and fail your dream garage tunnel project.

FAQs about Digging a Tunnel from House to Garage

1.   Which type of tunnel is easier to build?

If you’re a novice in tunnel construction, you should build a cut and cover tunnel. Because here, you won’t have to construct a ceiling to hold the weight of the soil. Besides, you don’t need any heavy types of machinery for digging.

2.   What is the approximate cost of building a tunnel from the house to the garage?

The cost of tunnel construction depends on your tunnel design and materials.On average, it’ll cost around $20K to build a tunnel to your garage. Again, if you want to have wood frames inside the tunnel, it’ll increase the cost. Consult an engineer to know more about the tunnel construction cost.

3.   Should I dig the tunnel by hands or use machines?

Digging the tunnel by hand requires a lot of time and effort. On the other hand, using machines fastens the process but requires more money.

4.   Do I need a mineral permit before digging the tunnel?

Yes, you may need mineral permits for constructing the tunnel. Contact your local authority for more details.


Constructing a tunnel isn’t easy. It requires a lot of physical work and a proper design. If you want your tunnel to last, you must hire an engineer and design the tunnel properly.

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Hi, I am Brent Hartman. I am a DIY enthusiast and love to improve and organize the garage in the most innovative way. I created this website out of my passion for helping people organize their garages.

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