Crawl Space urine type odor may not be due to the family cat. | Volunteer Mold and Indoor Air Quality
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Call Now! 865-385-0170

Does your Crawl Space Smell Like Cat Pee?

Young woman in a sundress holding her nose closed

Odors in homes and at work are NOT Normal. Ask Volunteer Mold and Indoor Air Quality for Help!

We frequently get calls from clients, who have sometimes spent thousands of dollars on crawl space encapsulation systems and from folks with typical plastic vapor barriers, complaining of a strong urine odor down below and in their homes.

Some inspectors have told me that its the plastics used or a family feline. I have found that this is often not the case.

A typical encapsulation requires sealing off acres points of entry for air. By installing panels and sealing up opening where air from outside getting in this typically precludes animal entry.

The claim some misguided inspectors make is that its an off gassing of the plastic materials. This is also not true. Many think the thick vapor barrier installed would be non permeable to moisture and odors. While well installed vapor barriers do well to keep moisture out of the crawl space we find many barrier installations that fall way short of optimal installations.

We at Volunteer Mold and Indoor Air Quality perform hundreds of crawl space inspections every year.

Heres where we start with an encapsulation inspection:

With a good light and knee pads, we inspect the complete crawl space paying special attention to barrier seam overlap, foundation vent seals, door gasketing and penetrations made for plumbing and electrical runs through the sub flooring.

We pay attention to Heating Ventilation and Air Conditioning (HVAC) connections within the crawl space and inside of the home.

Assuming it all checks out good and proper we turn to the science of gasses and probable causes.

Heres a video for more information. 

Here’s a neat graphic on how the ammonia odor comes from beneath the barrier and in the Crawl Space and Home:

Graphic on how soils can emit high ammonia levels

How plant materials in soils under your home turn into ammonia gas the smell like cat pee.

Got a question about your Crawl Space? Call Volunteer Mold and Indoor Air Quality before you evict your kitty.


Volunteer Mold Inspector Bob poses in a laundry room in front of Chlorine Bleach container.

Bob Byrne owner and operator of Volunteer Mold and Indoor Air Quality is expert in Inspection and Diagnosis of building environmental issues.

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