Can you dig down to make a basement?

Author: Maudie Kutch  |  Last update: Friday, October 17, 2025

According to U.S. residential building codes, you can only dig a basement that's one floor deep. Usually, that equates to a ceiling height of about 8 to 10 feet.

Is it possible to build a basement under an existing house?

Yes, it is possible to build a basement under a house that has already been built, but it's a complex and expensive process. It often involves excavation, structural reinforcement, and potentially temporary support of the existing house. Engineering expertise and proper permits are essential.

Can you dig down to make a basement taller?

Yes. It's actually pretty simple and just as you said-you dig it deeper. Get a jackhammer and remove the floor, shovel out the dirt until it's a suitable height, repour. It probably isn't worth the cost.

Is it legal to dig a basement?

In simple terms, homeowners across the Golden State can construct basements as long as they are built in accordance with the safety guidelines enshrined in the state's city codes and construction laws. Historically, basements haven't been as common in California compared to other parts of the country.

Can I build a basement on my land?

Yes, that is perfectly feasible. It also depends on your region's weather and the depth of the frost line in your area. Otherwise, yes. The basement does not have to mirror the footprint of the home. The rest of the footprint might be a crawling space if that is needed in your area. Best of luck!

How a Basement Digout is Done by Hand

Is it possible to dig your own basement?

Simply put, digging out a basement under a home on your own is a bad idea. Some environmental safety experts regard excavation as the most dangerous type of construction project. Even if you could rent the necessary heavy equipment, the risk to your safety and your home's structural integrity is large.

What states do not allow basements?

Where the water table is high, it is simply not feasible to dig too deep underground. In Florida, Alabama, Louisiana, and Eastern Texas, the soil is particularly damp, which explains the minimal number of basements there.

How much does it cost to dig and build a basement?

You might need a basement if you're dreaming of extra storage space, more rooms, or a place to entertain. Digging a basement beneath your home costs $37,000 on average, although it can go as low as $12,000 or as high as $150,000. Size also impacts the cost, and you can expect to pay $75 to $150 per cubic yard.

What is considered an illegal basement?

However, to be considered legal, a basement apartment must meet certain criteria including (but not limited to) minimum ceiling height, a minimum number of windows and exits, and possibly even having its own utility meters.

Do basements require a permit?

The simple answer is YES! You need a permit to remodel or finish your basement or any part of your home, for that matter. However, there is so much you must understand about permits, how to get them, why you need them, and when.

Is it worth digging out a basement?

Digging out a basement increases a home's square footage and resale value, especially if the basement is walkout or rental space. However, the project is expensive and may not provide enough return on investment (ROI) to be worth it.

How much does it cost to make basement taller?

Raising a Basement's Ceiling Cost Breakdown

Raising a basement ceiling typically costs about $19,200 and can range from $16,000 to $24,000. During this process, the house is lifted and the foundation is raised to a new level.

How far down can you build a basement?

Most people like their basement to be 8 feet deep, with about 30 inches of that being above ground to allow for windows. Of course, you can dig even deeper, but that will increase the cost.

Is it cheaper to add a basement or a second story?

Generally speaking, building up tends to be less expensive than a basement. That said, not too long ago, lumber was at an all-time high and basements were the better option.

Do you need planning permission for a basement?

Planning permission is usually required for basement projects, but not always. You will always need permission if you live in a flat or listed building; for a lightwell; for related works to fences and walls; to trees in conservation areas and to trees covered by Tree Preservation Orders (TPOs).

How much does a 2000 square foot foundation cost?

A foundation costs $6 to $50 per square foot, depending on the type. A standard 2,000-square-foot concrete slab foundation costs $12,000 to $28,000, while a basement foundation costs $70,000 to $100,000+. The best foundation for your home depends on the soil conditions, water level, and frost line in your area.

Are basement bedrooms legal?

A room in the basement cannot be considered a bedroom unless it meets specific qualifications and codes. In order for a room in the basement to be counted as a bedroom, it often needs to meet the following basement bedroom requirements: A legal window (egress window) 7-foot-tall ceilings.

What does it mean if a basement is not permitted?

Consequences of Finishing a Basement Without a Permit. Failing to obtain the necessary permits before finishing a basement can have negative consequences. These can range from financial penalties to safety concerns and even legal issues.

Why not to have a basement?

Basement Cons

Even with a daylight basement, which has small windows near the top of a wall, basements generally will not have very good, if any, natural lighting on the lowest level. Humidity. Basements can be humid and susceptible to mold and mildew growth.

Is it cheaper to dig down or build up?

So which option is the best option: Building Up, Down, or Out? In summary: The best option for those looking to save money is building up.

How hard is it to put a basement under an existing house?

The difficulty of adding a basement to an existing house can vary depending on the house's location, the size of the basement, and the type and condition of the existing foundation. Adding a basement is a job best handled by the pros, so you'll need to enlist professional help for this project.

Is it cheaper to build a house on a slab or basement?

Slab is less susceptible to termites or other pests because there are no open spaces. Slab foundations cost about $10,000 less than those with a basement or crawlspace.

Is it illegal to live in a basement without windows?

The International Residential Code (IRC) requires all habitable spaces to have at least one exit from any point in the room. You can find the basement egress window codes for many US states on our website.

What is a yankee basement?

A so-called “Yankee” basement is a subterranean basement with all four sides completely underground; there is no open daylight side providing direct access to the basement. Rather, to gain access, these basements have an angled cellar door or diamond-plate sidewalk door with steps down below.

Why is there no basement in California?

Reasons Why Homes in California Don't Have Basements

California homes don't have basements because of climate conditions, traditional architecture, and the perceived risk factors of adding a basement in an earthquake-prone area.

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