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How Much Does It Cost to Build a Crawl Space?

How Much Does It Cost to Build a Crawl Space?

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A crawl space foundation may be costly, but it’s the most convenient option for sloped areas and earthquake-prone locations. It creates an open-air space underneath the house for ductwork, plumbing pipes, and cables, so people often prefer it over a slab foundation.

But how much does it cost to build a crawl space?

The answer depends on the condition of your building area and the size of your house, but a crawl space will cost you anything from $8,000 to $25,000.

Here’s a breakdown of the building costs of a crawl space:

How Much Does a Crawl Space Foundation Cost?

A crawl space can cost you $8,000–$25,000 to build, depending on many factors. You typically pay less if you decide to build it yourself, but if you’re getting a contractor, it will cost you from $10,000 upwards.

The major deciding factor is the condition of the site you’ll use to build the crawl space. If it’s level ground with dry conditions, it’ll cost you around $12,000 to $14,000 to build a 1000-square-foot foundation.

On the other hand, if the site is challenging, you’ll likely pay more to build the crawl space. For example, the ground may be slightly sloped, or the area may be prone to plenty of rain. In that case, the crawl space will cost you $13,500 to $15,500 for a 1000-square-foot area.

Some sites are extra challenging due to poor conditions. For example, if your site has a harsh slope or a lot of trees, you’ll have to pay a lot to set the foundation.

The same goes for frosty areas because the support footings will have to be higher. In that case, the crawl space will cost you $16,000–$25,000 for a 1,000-square-foot area.

So, to sum it up, here’s a roundup of how much it’ll cost you to build a crawl space:

  • Good site: $12,000–$14,000
  • Slightly challenging site: $13,500–$15,500
  • Highly challenging site with possible frost: $16,000–$25,000

How Much Does Crawl Space Cleaning Cost?

A crawl space is an area of your house that typically sees little to no traffic, so it’s the perfect site for mold to grow and for pests to breed. That’s why you should clean it at least twice a year, or else worse issues will arise.

The cleaning can cost you anything from $750 to $5,000, depending on the space’s condition.

Here’s a roundup of cleaning types and treatments and how much each of them cost:

Debris/Dust Cleaning

If all your crawl space needs is a basic cleaning to remove debris and dust, you’ll pay around $750–$1,500 to get a professional company to do it. Larger spaces will cost more, so if your crawl space spans an area of 1,500–3,000 square feet, expect to pay $3,000 or more.

Additionally, if your crawl space is hard to access or shorter than 3 feet, the cleaning company will likely charge you more than the average rate.

Mold or Fungus Treatment

Crawl spaces are highly prone to mold because they’re humid and narrow. Areas with plenty of rain serve an even bigger risk because the moisture can eventually cause mold to grow.

If you get a professional company to clean the crawl space, they’ll charge you $1,000–$2,000 for mold removal. They’ll likely isolate the area and use anti-microbial sprays to treat the mold, so if you think it’s better to save the money and do it yourself, it’s actually better to leave it to the pros.

Fungus treatments usually cost the same as mold treatments, depending on the severity of the condition.

Pest Treatment

Unfortunately, crawl spaces are ideal places for pests to breed. Whether it’s rats, mice, termites, or any possible types of pests, once they find their way into your crawl space, it’ll be hard to get them out.

Getting a pest eradication service will cost you an average of $1,000–$3,000, depending on the extent of the infestation.

How Much Does It Cost to Install a Vapor Barrier in a Crawl Space?

One of the drawbacks of having a crawl space foundation is dealing with high levels of humidity. If you don’t have a moisture barrier, the humid air will get absorbed up into the flooring, and from there on, it’ll only go downhill.

That’s why a vapor barrier is essential, and it costs an average of $5,000 to install. Depending on the size and condition of your crawl space, the cost can go down to $1,500 or up to $10,000.

Here’s a rundown of all the factors that go into pricing:


If your crawl space needs significant repairs before installing the vapor barrier, it’ll typically cost you more to encapsulate it.

You may have to pay $2,000–$5,000 to repair any walls and joists affected by water damage. If nothing needs repairing, you may only need to clean the space and get rid of any dust and debris, which should cost $500–$1,000, depending on the size.


Size is the major deciding factor when it comes to installing a vapor barrier. It costs an average of $3–$10 to install the barrier per square foot, so do the math depending on the total area of your crawl space.

Vapor Barrier

The vapor or moisture barrier is often polyethylene sheeting that lines the foundation walls. Its cost differs according to its thickness. Thinner sheets will cost around $0.05–$0.20 per square foot, while thicker varieties may cost up to $0.50 per square foot.

You’ll choose according to the humidity level in your area; a thicker barrier typically offers more protection.

Waterproof Tape

To install a vapor barrier, you’ll need waterproof tape for sealing all the edges. It should cost you $10–$20 per roll, so the total cost depends on the size of your crawl space and how many rolls it’ll need.

How Much Does It Cost to Fill a Crawl Space?

If you live in a flood-risky area, filling your crawl space may be worth considering. It’ll cost you thousands, but it’ll protect your house from the damage floods can cause because it’ll raise the lowest load-bearing point of the house without actually lifting it.

The process is usually done by filling the crawl space with gravel or sand up to ground level. It doesn’t seem like a big deal, but you’ll need permits to do that because filling in your crawl space can damage the house’s structure. It’s also better to get a professional opinion before doing it.

The permits will cost you around $200 on average, while filling the crawl space will cost $5 per square foot, depending on its size and condition.

Final Thoughts

So, how much does it cost to build a crawl space?

It can cost you anywhere from $8,000 to $25,000, depending on plenty of factors. You’ll pay a larger sum if you’re building the crawl space on a sloped ground or in a rainy area. Meanwhile, you’ll likely pay less than $10,000 if you decide to make it into a DIY project.

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