Causes of Crawl Space Cat Urine Smell
Crawl space odors are difficult to deal with, and one of the worst is the cat urine smell. Many crawl spaces suffer from cat pee odors, and often times the vapor barrier is the cause. Whether directly or indirectly.
The type of plastic and installation methods can create cat urine type odors in the crawl space. Eventually, these odors enter your home, so what can you do to fix this issue?
4 Common Causes of Crawl Space Cat Urine Smells
We find the cat urine smell in many crawl spaces comes from 4 common sources.
- Feral cats using the crawl space as a litter box
- Cheap vapor barriers that allow moisture to penetrate them and eventually grow odor causing bacteria
- Crawl spaces not properly ventilating odoriferous soil gases
- Crawl space plastic installed over old vapor barrier
As you can imagine, the first one is not something we deal with, so I recommend you call a critter wrangler company for that. The other three, I will discuss why the odors are happening and what to do to protect your crawl space.
New Vapor Barriers Can Have Odors from the Manufacturing Process
Some vapor barrier manufacturers say I am a reinforced plastic hater, and that simply is not true. I used to install crawl space vapor barrier with reinforcement until I learned the potential of odors building up due to what I consider a design flaw. It may or may not be due to the reinforcement itself, but that the reinforced plastics are multilayer.
The Drawbacks of Using Reinforced Plastic as Vapor Barriers
If a multilayer vapor barrier is installed and reinforcement is present, it can have air gaps. The cheaper the plastic it seems, the more the air gaps. If I install plastic with air gaps on wet soil and the air is replaced with water and stagnates, what happens?
Odors!
Once the water infiltrates the air gaps located in reinforced plastic, it rarely leaves. Due to this potential odor issue, we only installed solid vapor barrier.
The Mystery of Odors and Reinforced Plastic in Crawl Spaces
I know many blame soil gases alone for this problem, but I interviewed a homeowner on our YouTube channel that shared his experience. Feel free to listen to the entire interview. But he said he could smell cat urine smell before the plastic was placed in the crawl space. That’s right, if cat pee odors only came from soil gases, why was the plastic giving off a urine odor before installation?
Soil Gas Odors
Many of the soil gases that enter the crawl space are a combination of gases. All of these gases mixing together could smell like urine or ammonia or something else. By the way, ammonia is a component of cat urine. According to petmd.com, if cats smell ammonia, they are likely to urinate there.
Soil can off gas many types of gases. The primary three are:
- Nitrogen
- Carbon dioxide
- Oxygen
On a side not when asking where the make-up air comes from when you ventilate an encapsulated crawl space, most likely the soil. Other gases that come from soil include:
- Nitric oxide
- Nitrous oxide
- Methane
- Ammonia
Man, I feel sorry for anyone with ammonia and methane gases in their crawl space. A farty urine smell must be rough.
The point is, all crawl spaces are dealing with soil gases. This is why we recommend ventilating the crawl space, especially after crawl space encapsulation. This ventilation is done per EPA guidelines of 1cfm per 50 square feet of crawl space.
Keep in mind, some soil gasses are odorless. Unfortunately, they tend to be the most harmful. Radon gas is colorless, odorless and virtually undetectable without proper testing. In crawl spaces where radon is present, install a sub-membrane depressurization system to protect your home and family.
Installing New Plastic Over Old Plastic
The fourth issue we see that can create cat pee and other odor problems is new plastic over old. Just like some cheap roofers will install new shingles over old shingles, but reputable roofers do not. We feel installing new plastic over old serves no long term benefit, and the reasoning for doing it is to save money.
The Importance of Proper Crawl Space Encapsulation to Prevent Odors
The effects could be the build up of mold and other biological matter that can smell horrible. Here is a customer testimonial of someone that had a cheap crawl space company install new plastic over old. The smells went away once they hired us to remove all the plastic and install even newer plastic correctly.
Unfortunately, sometime the fix for crawl space odors is a crawl space encapsulation redo. This is why you should hire the best crawl space contractor to do it right the first time.
Contact Crawl Space Ninja for Basement Waterproofing and Encapsulation
Please contact us to schedule your assessment to fix your crawl space, basement issue.
Do you need help with mold removal, crawl space encapsulation, crawl space insulation, vapor barrier, waterproofing, foundation repair, basement waterproofing, or controlling humidity in your crawl space?
If you live in Georgia, Delaware, North Carolina, South Carolina, Tennessee, or Kentucky, Crawl Space Ninja can help!
Also, let us know in the comments below if you have an idea for a new blog topic.
DIY Crawl Space Repair
Perhaps you’d like to tackle your own crawl space repair. Visit our DIY Store.
Join Crawl Space Ninja as an Owner
Learn about Crawl Space Ninja Franchise opportunities.
Ready to find out more?
Drop us a line today for a quote!
