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Three Reasons You Should Not Use Lime in Your Crawl Space

crawl space with insulation and vapor barrier

Recently, one of our project managers encountered a new DIY “solution” in a customer’s crawl space.  The homeowner had spread lime powder over the top of their vapor barrier, in an attempt to absorb moisture and odors.  After doing  some research, I was alarmed to learn that this was an idea recommended by some DIY websites.

Acculevel is a family-owned and operated company that specializes in repairing foundations,  installing egress windows, and waterproofing basements and crawl spaces.  Our goal is to provide homeowners with a complete home solution that protects and preserves your greatest investment.  We use the highest quality products, installed by our exemplary crews, and provide some of the best warranties in our industry.  

We believe everyone should have a safe and healthy place to live, and we try to answer questions and concerns from our customers promptly and thoroughly.  In this FAQ, we’re going to explain why you should not put lime in your crawl space to absorb moisture.

crawl space with insulation and vapor barrierThis photo was taken by an Acculevel crew member after we repaired sagging floors and installed a vapor barrier.


What is “Lime” and How is it Used? 

First of all, we are not talking about green citrus fruit.  Lime dust, lime powder, hydrated lime- these are all names for the chemical compound calcium hydroxide.  

Calcium hydroxide is used in a wide range of industrial applications: removing impurities from steel during manufacturing, producing mortar and cement, and treating sewage and petroleum waste.  It is, in fact, an extremely useful chemical product- just not for residential use.


Three Reasons You Should Not Use Lime in Your Crawl Space

On paper, lime seems like a logical option.  It can absorb moisture, which is why it’s used for treating waste and spilled chemicals.  And it could be used for pest control, because it’s fatal if ingested.  However, there are significant downsides to using it for either of these purposes.


1. Lime Can Only Absorb a Limited Amount of Moisture

You can’t expect a one-time application of powder to cope with ongoing water seepage.  It’s a “one-time” application because it will only work for one instance, like a spill or sewage leak that is being repaired.  Once the lime has done its job, it needs to be removed and disposed of in an environmentally safe manner.

If you have water getting into your crawl space, you need to determine the source and take the appropriate action.  A crack in your foundation should be repaired, not only to stop water but to preserve your foundation’s stability.  If your guttering drains too close to your home, extend the downspouts. (Downspout extensions are a DIY we fully endorse!)  And if the water is coming up through the dirt “floor” of your crawl space?  It’s time to consider installing water drainage.  


2. Lime is Hazardous to the Touch

I mentioned earlier that lime could be used as pest control; that does not mean it should be.  Lime can be fatal if ingested, and that means to any animal- including pets and people.  While it isn’t particularly likely that you or Fido will eat lime powder, it doesn’t have to be ingested to harm you.

Skin exposure to lime can cause severe burns and skin corrosion.  If particles of calcium hydroxide get into your eyes, you can suffer tissue damage and blindness.  Anyone who is going to work with the lime substance should be properly outfitted with the appropriate PPE (personal protective equipment).  This PPE includes chemically resistant clothing, gloves, boots, and safety goggles. 

This means you are risking your safety if you work with lime powder.  And any service technician or contractor who needs to access your crawl space is also at risk.  These could be plumbers, electricians, or contractors (like our project manager).  This could easily become a legal issue- especially if you don’t disclose it to the technician in advance.   And if you do disclose it, they may refuse to do the work or charge you additional fees for acquiring the necessary PPE. 


3. Using Lime in Your Crawl Space Compromises Your Home’s Air Quality

If lime dust can cause burns and tissue damage on contact, imagine what happens if it’s inhaled!  Inhalation of calcium hydroxide can cause burns in the throat and esophagus, swelling and irritated tissue, and difficulty breathing.  

Air that is in your crawl space can -and does- move into your home’s air.  The lime dust you’ve spread on the ground under your house could be stirred up by a number of things: the HVAC unit kicking on, wind gusts getting through cracks, even animals or contractors accessing the crawl space.  

Once those lime particles are airborne, what’s keeping them from getting into your ventilation system? Your HVAC pulls air in, heats/cools it, and blows it into your home.  Maybe it’s not letting a large amount of lime dust in, but how much does it take to irritate your eyes? Or cause lung irritation in someone with asthma?  Given how many other pollutants and allergens are already in our environment, do you really want to add a harmful substance to the mix?  


Additional Resources

Are you curious about the purpose of a vapor barrier?  This article explains why you should have one in your crawl space.

 If you don’t have standing water in your crawl space, but it feels damp and smells musty, a dehumidifier may be the solution you need.  

The absolute best way to ensure you have excellent air quality and a dry crawl space is through encapsulation.  


Do You Have Concerns about Your Home’s Crawl Space?

Are you the DIY type of homeowner?  Then you should take advantage of our DIY Home Inspection Checklist.  You will learn how to evaluate your flooring structure, foundation walls, landscape- all the areas of your home that can affect your foundation’s health and stability. 

If you find problems or concerns, you can learn more about symptoms and causes with another one of our free tools: the symptom checker.

link to symptom checker


Do You Need a Professional Assessment of Your Crawl Space?

If you live in Indiana or the surrounding area, call Acculevel.  When you fill out our contact form, one of our friendly call center employees will reach out to you within 48 hours.  They will schedule an appointment for you with one of our knowledgeable and experienced project managers.  The project manager will evaluate your home and address your concerns, then recommend a whole home solution to keep your home strong and healthy for years to come.

If not, you’ll want to find a reputable and insured local repair company.  We recommend that you verify they are accredited by the Better Business Bureau.  If you need help finding a local contractor who is good fit for your home, this blog provides resources you can use


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