How to build basement under existing house

How to build basement under existing house. Usually, things look easier when they happen in order or follow a sequence to get accomplishment. It gets less tricky, less challenging, and faces fewer risks of any loss.

Here we are talking about constructing a basement under an existing house. Well, someone who doesn’t know it can happen must consider it a silly joke.

As we know, the basement is a house character that always plans to construct first by the constructor, but the human mind is tricky and can jumble its plans sequence according to the situation or needs.

If you are interested in how to build a basement under an existing house, then here you will get the detailed answer to that exciting query. It’s challenging and requires professionalism so let’s start diving into the procedure.

A Perfect Guide For How to build basement under existing house

Many people prefer a basement, so they would like to purchase a house with a built-in basement or make a basement first while making a house, and others create the basement later under a house.

The constructors build a basement by lifting and holding the house. Propping up the house tied the house from moving, which may prevent damage to the house structure.Building a Basement Under Existing House

After bracing the house, provide its firmness, and you may consider hiring a laborer to do the digging. The cost for the following task depends on different factors, such as area and location.

Well, after that, the contractor proceeds with the underpinning. It would be helpful to have some space on your right, left, or in front of your house to transmit dug soil through relevant machinery.

After completing the digging, the other tasks considered include draining the system, water supply to do some electric wiring, and waterproofing your basement and walls.


Don’t forget to take a legal building permit for building the basement without any interference. Secondly, you must act upon the building code of your area.

Other Tips You’ll Consider For Building Basement

The first and the most crucial thing we want to recommend is, don’t think to build it yourself as it requires work experience and professionalism to tackle the existing house, so contacting your area basement constructor would be best.

So, don’t take any risks if you are unaware of the pro skills for holding and releasing the house after building the basement. You can surely get the knowledge for what your basement requires for building, as mentioned.

Other things you require are written below:

Water Proofing

Waterproofing is one of the prime factors you should consider while planning a basement. You may schedule the waterproof wrap coexistence with the walls and the ground.

It enables safety to the walls and floor, so you require waterproofing on the outer side of the walls and underneath the ground surface like a safety wrapping.


Lighting is the next factor you have to think about to make a plan. Even making a house, we never forget to make windows for ventilation and lightening the room.

A basement is where it’s hard to get natural light and fresh air but not impossible. You may consider making glass windows with open and close features at the top sides of the wall by lowering the lawn or making doors through the stairs.

Well, the choice is all yours. If the situation enables you to get natural resources, go for it; otherwise, you may do some wiring to utilize some LED lights.

Drainage System

The draining system is also an essential factor that you must consider while building a basement. A failed draining system may lead to severe issues like deluge and leakage.

Excavation Tools

As you may know, digging a basement is not easy, so you require some machinery that may cope with the digging task of soil and rocks and empty the basement with excessive soil to make free space.

Empty The Neighboring Area

A basement added the extra space but building a basement requires extra space. You will surely need a place to throw soil and place machinery and material for building the basement.

You may prepare the lawn for doing the job if you have a lawn. Remove all the accessories and interference from the place. If you don’t have a lawn, look around the neighborhood.

If there is, you can go for a direct conversation and may request to borrow their place for your use. If you find them friendly, they will indeed allow you. Otherwise, your contractor will surely know his way of the job.

Cost & Time

Different factors impact the cost and time. The location, area of the planned basement, and structure are the things that may impact cost and time.

As the basement used to proceed with different tasks that we have mentioned before so you can estimate the time from its starting to finalize the basement may take period near to one year.

  • Cost for excavation, installing basement, and water proofing= 3 to 5 months.
  • Basement finishing time= 4 weeks to 2 months.

If you talk about the cost, it may cost you 50 to 75 dollars per sq ft.

  • Underpinning, excavating, and basement with concrete foundation =500 to 1500 dollars.
  • Location, measurement, and the material like underneath soil or rock of your existing house may reach up to 50000 dollars.
  • Other expenses like windows, doors, lighting, exhaust fan, and ceiling may cost from 1000 to 100000 dollars.

Pros Of Building Basement

If people decide to have or build a basement in any way, a basement must carry a few advantages. So, you may consider them.

The most crucial purpose of building a basement is to extend the living area of someone’s house. Undoubtedly, it’s an effective way to add a story and increase the space without buying an extra property.

Especially when you don’t have an empty place around or don’t have a free space like a yard to broaden the area of your need, one more thing that you need to remember is all the lands are not fair for building a basement.

The other benefits of the basement are preserving food and saving yourself in intense climates. You can also use it casually or dedicate it to an entertainment zone like a cinema or gaming zone.


If you plan to build a basement under an existing room, then the following guideline is enough to give details. The purpose of the guideline is to inform you of the vital factors essential to remember while planning to build a basement under a house.

You can estimate the time and cost according to the area and basement location. After making a complete plan, you may hire a contractor to discuss your plan and to give the contact for it.

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