How Deep Can You Build a Basement?

A basement can be any depth as long as it abides by building codes and local regulations. Typical basements have a depth of around 8 feet. They are built on concrete slabs that have a minimum thickness of 4 inches. The deepest basements are multi-level basements.

Have you ever thought about how deep can you go for your basement? It turns out the standard answer is up to 8 feet. Going deeper means you have to spend more this is why most basements are 8 feet or shallower while basements dug deeper than 8 feet are mostly seen on commercial buildings.

How deep can a basement be?

A regular basement is dug up to 8 feet deep. This is the depth of the 4-inch slab the basement is built upon. However, you might need to dig deeper than 8 feet to provide a foundation for the cement slab that you build your basement on.

Is 8 feet enough depth for a basement?

8 feet is the maximum comfortable and affordable basement depth. You may encounter water at a lower depth. 20 feet basements are typically already facing multiple water infiltration problems and planning to route the water around the basement is required down at 20 feet.

Can I park my car in an 8 feet basement?

A normal estate car is up to 6.7 feet tall. This means if your dig a basement of up to 8 feet you should even be able to construct an underground garage to park your car in.

Can an 8 feet basement be turned into a bedroom?

A standard room is up to 8 feet tall. This means you can dig a basement that’s as tall as a regular room in most situations.

When do you need to dig a deeper basement?

You don’t always need to dig an 8 feet basement. Sometimes you dig more while other times you dig less as follows.

  • When building a multi-level basement

You can dig down to 16 feet when you build double-level basements. These are common in busy urban areas where building up or sideways isn’t an easy option.

  • When building a partial basement

Building a partial basement means you’re only building a basement under a smaller area under your home. This type of basement is ideal either as a kitchen, a spare room, or a storage room. In other cases, it’s used for HVAC and other heating solutions which means the room doesn’t have to be exactly 8 feet from floor to ceiling.


You can build a basement as deep as you want if you abide by regulations and if you have the money. Deep basements for large homes cost at least $50.000. These costs can double when you decided to dig even deeper. However, deeper basements are very popular in high-rise buildings and other commercial-purpose buildings.