Cost to Convert a Crawlspace to a Basement (Detailed Rates)

Gary Evans
by Gary Evans
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cost to convert a crawlspace to a basement detailed rates

The crawlspace often winds up as an underutilized part of the home mainly because it isn’t comfortable. If you want to make that crawlspace more functional, you should consider converting it into a basement. Before embarking on this big project, you should know the cost to convert a crawlspace to a basement is very expensive.

To convert a crawlspace to a basement costs $50 a square foot, or about $60,000 to $150,000 to add 2,000 square feet. Architects charge $2,000, or $8 per square foot, to draw up the plans for a crawlspace conversion. Digging out the crawlspace costs between $10,000 and $30,000. Plumbing alone costs $6,500, and adding stairs adds another $2,000 to the project.

A new basement could become a bedroom for one of your kids once it’s finished properly. You can also turn it into a small entertainment area or use it as a guest room. Read through this article if you want to find out how much converting a crawlspace into a basement will cost.

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Many Factors Influence The Cost To Convert Crawlspace To A Basement

Make no mistake, converting a crawlspace into a basement is a giant undertaking with many moving parts. It’s not just about digging out the space and putting up some walls and paint. You need to consider plumbing, electrical, waterproofing, and so much more.

Hiring An Architect: The Cost To Convert Crawlspace To A Basement

Estimate TypeCost
Low-End Estimate$2,500
Mid-Range Estimate$4,000
High-End Estimate$7,500

If you’re planning to convert your crawlspace into a basement, you need to start by hiring an architect. For $4,000, an architect will draw up the plans that a contractor can follow while building the basement.

Hiring an architect is necessary because they will ensure that your new basement will be structurally sound. On top of that, they can also come up with plans that comply with the building code in your area. Thanks to the architect’s involvement, you won’t have to worry about securing the permits when the time to build arrives.

Note that $4,000 is the average fee that an architect will charge if you need a building plan for your basement. Their asking fee could change depending on their preferred payment structure.

Based On Hourly Rate

Many architects charge by the hour. The exact hourly rate usually depends on the level of the architect’s level of experience. An architect with the experience and knowledge you need will charge an hourly rate of $120.

That number may seem low, but drafting plans for a new basement can take a long time. The architect has to study the structure of your home and figure out if it can accommodate a new basement. They have to consider if adding the basement could potentially weaken the rest of the home.

All that studying and planning takes time. Be ready to pay a hefty fee to compensate them for the time they’re dedicating to your project.

Based On Square Footage Of The Project

Some architects go with a fee structure that’s based on the square footage of the project. They usually charge $8 per square foot.

You may be able to save some money by finding an architect who bases their fee structure on square footage. Of course, that assumes you’re keeping your new basement on the small side.

Architects who prefer this kind of payment structure are hard to find. Don’t be surprised if you cannot find one in your neck of the woods.

Based On Percentage Of The Project Cost

An architect may also propose a payment plan that is based on how much the project will ultimately cost. To be more specific, they will ask to be paid a set percentage of the project’s final cost. Architects that prefer this type of payment structure usually ask for 12 percent.

Agreeing to this kind of payment structure can be a risk on your part. You have to find out early on how much the project is likely to cost before you sign off on the deal. If you cannot determine what that figure will be, you should probably look for a different architect.

Cost To Convert Crawlspace To A Basement: Digging Out The Crawlspace

Estimate TypeCost
Low-End Estimate$9,000
Mid-Range Estimate$20,000
High-End Estimate$30,000

Once the architect gives you the plans for your new basement, you can proceed to the next stage of the project. The next stage involves digging out the crawlspace to make room for the new basement. Digging out the crawlspace costs a lot of money, with contractors normally charging $20,000 to take on that job.

This part of the project is going to take a lot of time. Since the crawlspace is located underneath your home, the workers cannot use excavators to dig out that area. They will have to create the space you need for your new basement the old-fashioned way.

Hopefully, there are no large obstructions in that crawlspace so the digging doesn’t take too long. If there are obstructions there such as concrete slabs, the digging will be harder to finish. They will need to bust through the concrete first before the crawlspace can be fully carved out.

Once they finish digging out the crawlspace, the workers can also raise that part of your home. Raising your basement is not often required. You’ll have to refer to the soil conditions to determine if raising the basement floor is needed.

Cost To Convert Crawlspace To A Basement: Building Retaining Walls

Estimate TypeCost
Low-End Estimate$3,000
Mid-Range Estimate$5,500
High-End Estimate$8,500

The next step involved in converting your crawlspace into a basement is building the retaining walls. Constructing the retaining walls that are required for your new basement will cost $5,500.

You need to build retaining walls for two reasons. First, you need those retaining walls to pack the soil behind your basement.

If the soil surrounding your basement shifts constantly, that part of your home could wind up damaged. You can use the retaining walls to ensure that they won’t move around too much.

The retaining walls can also be used to lend some additional support to your home. They will keep your home’s foundation from getting weaker over time.

Different materials can be used to create the retaining walls. Some commonly used materials include bricks, steel, and wood. For this particular project, you should stick to using concrete. Those concrete walls can help solidify the perimeter of your basement. Concrete retaining walls are also easier to build since the material can be poured in instead of carried into that space.

Cost To Install Plumbing

Estimate TypeCost
Low-End Estimate$3,000
Mid-Range Estimate$6,000
High-End Estimate$10,000

Before you pour in the concrete for your new basement floor, you may need to rework your home’s plumbing system. Adjusting your plumbing system to make room for your new basement will cost an average of $6,000.

The plumber will have to create new pathways for your pipes underneath the new basement floor. Now is the right time for them to rearrange the plumbing because they won’t have to deal with obstructions.

Reworking the plumbing is not always necessary if you’re converting a crawlspace into a basement. Perhaps you never had any plumbing that ran under your crawlspace. In that case, you can just jump ahead to the next phase of this project.

You can also install new plumbing even if the pipe network in your home does not require it. Installing new plumbing allows you to accommodate more fixtures in your new basement. Build a bathroom down there so occupants are more comfortable.

We’re not getting into the cost of building a new basement bathroom, but it will be expensive. It will cost more than building a normal bathroom because it’s a more complex project.

Cost To Convert Crawlspace To A Basement: Pouring Concrete For Floor

Estimate TypeCost
Low-End Estimate$6,000
Mid-Range Estimate$13,000
High-End Estimate$21,000

We’re nearing the end of this crawlspace conversion project. For this next step, you can pour in the concrete that will make up your new basement floor. Your new poured concrete floor will cost $13,000.

Many homeowners opt for poured concrete floors because it’s cost-effective. $13,000 is a lot of money, but you’ll have to pay significantly more if you want a different type of floor.

Poured concrete floors are also easy for homeowners to watch after. Once the concrete has solidified into a floor, homeowners don’t have to do much to keep it in good condition. That could be helpful if you don’t intend to be in your new basement all the time.

Workers also have an easier time pouring concrete as opposed to installing other floors. If you want your new basement finished as soon as possible, going with concrete is a good idea.

You have to make sure that the preparations have been made before the concrete floor is poured in. Double-check the plumbing before the concrete is poured because you don’t want the workers making repairs with the floor already there.

Cost To Build Basement Stairs

Estimate TypeCost
Low-End Estimate$1,200
Mid-Range Estimate$2,000
High-End Estimate$3,500

To finish up the conversion of your crawlspace into a basement, you will need to build some stairs. Your contractor can build the stairs leading to and from your basement for $2,000.

The stairs will serve as your main access point to your new basement. That basement staircase doesn’t have to be especially elaborate, but you can go in that direction if you are so inclined.

Wooden basement stairs are the most affordable and they are good enough for maintaining access. Still, you can construct a more eye-catching staircase by using stone, concrete, or even glass.

The new staircase can also be aligned in different. L-shaped and U-shaped staircases are cheap to build and they don’t take up a lot of space. If you want something more decorative, go ahead and build circular or arched basement stairs.

Cost To Finish The Basement

To finish the basement you need to frame the walls, add electrical, install floors, paint, etc. On average, you’ll spend a total of $15 to $20 per square foot to finish the basement. Here is a rough breakdown of what these things will cost you.

ItemLow-End EstimateMid-Range EstimateHigh-End Estimate
Wall Framing$1,000$1,750$2,500
Electrical Wiring$3,500$5,500$8,000
Drywall$1/square foot$2/square foot$3/square foot

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Related Questions

Is a crawlspace or basement better for your home?

When choosing between a crawlspace or basement, you have to consider certain factors. First off, consider the conditions in your area. If your area is known for flooding, building a basement may not be a good use of resources.You also have to consider your needs. If you need a new room for your growing family, then you should build a basement.Money matters as well. Crawlspaces are cheaper compared to basements. The state of your finances may influence what you ultimately decide to build underneath your home.In many cases, if you have the space below a room, it is easier to add an addition than convert a crawlspace into a basement. An addition can cost about $20,000 to $70,000 and won’t cause the potential damage that digging out a crawlspace would.Digging out a crawlspace usually requires jacking your home up, which can cause the drywall to crack. You also might face issues with your plumbing and electrical in your home, as well as need to redo your landscaping.

How much does it cost to lower a basement floor?

Lowering your basement floor may be required due to building codes in your area. You can also lower your basement floor to make that part of your home more accommodating. Homeowners usually have to pay $35,000 if they want to lower their basement floor.

What is a good ceiling height for a basement?

Building codes normally indicate that a finished basement’s ceiling must at least be seven feet high. Consider setting the ceiling higher if you want your basement to be as comfortable as possible.

Gary Evans
Gary Evans

Gary Evans is passionate about home improvement. He loves finding out how to make improvements in the easiest, most practical, and most affordable ways. Upgrading his home kitchen is one of his ongoing hobbies. Gary is also a long-time content creator and enjoys spending his free time tending to his hydroponic vegetable garden.

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