Crawl space issue

[Brian H]

I have a 1000 sq foot crawl space that has a distinct urine odor similar to cat urine. The urine odor is not noticeable in the house most times, except during times of high humidity and then only faintly.

The crawl space was encapsulated several years ago with a 12 mil thick vapor barrier. I suspect that the odor is coming from moles who had at one time invaded the area.

Any ideas on how to eliminate that odor in the crawl space? It's basically dirt covered with a thick layer of plastic.I can open areas of the cover to spray/fog under it.

 

[J Scott W]

Are you certian the urine odor originates under the vapor barrier? COuld it be in the floor joists or subflooring?

I would think the combination of heavy barrier and encapsulation would keep any odors originating in the dirt out of the home.

If it is in the soil, can you get some lime under the vapor barrier to encourage natural decomposition of the source?

 

[Brian H]

I am fairly certain that it is in the soil and not the sub floor or joists.

Pulling up the vapor barrier would be a chore, though it could be done. How much lime would need to be applied and would it have any impact on the vapor barrier once it's put back down?

 

[J Scott W]

I am fairly certain that it is in the soil and not the sub floor or joists.

Pulling up the vapor barrier would be a chore, though it could be done. How much lime would need to be applied and would it have any impact on the vapor barrier once it's put back down?

Richard may have more experience than I am be able to give a more exact answer.

We typically applied less than 1/4" of lime. Just enough to cover the ground with not many places where soil was visible.

I don't think it would affect the vapor barrier at all.

It may be possible to use air mvoement to "float" the vapor barrier and then blow lime underneath, especially if you knew or suspected an area to concentrate on.

Using Vaportek and air movement might be easier and worth trying first. Stand Alone cartridge (3X Industrial) for a few days or Vapor Sharek for 1 day should take care of it if it was going to work.

 

[Desk Jockey]

Sounds like an entrainment issue. If air or gas is backing up in to the house you probably should correct it.

I'd put in a low volume fan to put a slight negative pull on the crawl space. They don't draw much amps and can be easily installed using pvc plumbing.

That might do it and as you mentioned you only need to run it when the humidity is high.

Fantech FR100 - FR Series Round Inline Exhaust Fan, 4" Duct (137 CFM) - SupplyHouse.com
http://www.supplyhouse.com/Fantech-FR100-FR-Series-Round-Inline-Exhaust-Fan-4-Duct-137-CFM

 

[Nate The Great]

Off topic, with our shitty basic building code here we see problems with hardwood and laminate floors from crawl spaces....

My pops been a flooring inspector for a long time and said to correct most of the problems would be basically what @Desk Jockey said... But for flooring application, use a push and pull method... A fan on 1 side sucking and 1 on the other side blowing to create the "trade winds" that help to keep the humidity down for us... Hook it up to a humidity controller to automatically turn on and off...

He believes the "Air Exchange" will reduce the problems he sees...

 

[Desk Jockey]

They also make dehumidifiers for crawl spaces with humidistats. The key is doing as Brian as done and treat it as a part of the built environment. 10-12 mil sheeting controls moisture diffusion, then either the exhaust fan or dehumidifier.

Crawl Space Dehumidifier |Compact Air Plus #CAP-200
https://crawlspacerepair.com/crawl-...act-air-plus?gclid=COi0-aSQpM8CFQowaQodvYIF_g

 

[Old Coastie]

If the urine odor started recently, you very probably have rodents, cats, opossums, snakes, raccoons or bats getting in. Mice can enter a space though a 3/4" opening. Have a pest control inspector get in there and look for tracks and feces. It need not be an ongoing infestation to stink.
With seasonal changes, animals quite naturally seek moderate temperatures under houses.

Cure the problem with ventilation (tempvents) and application of enzymes or your favorite deodorizer. Then seal up all the openings with copper wool (chore girl), hydraulic cement and caulk.

If you must, replace the plastic vapor barrier with new, black (never clear) sheet. You don't have to be fancy, just get it in there.

Good luck!

 

[Mikey P]

Any Eucalyptus trees in the area?


same odor to my nose

 

[tcfinest]

The key for encapsulation of a crawl space is that is be completely sealed this included all vents & seams. You have to have 100% control over the climate down there in order to eliminate odors & high humidity. Check out Basement Systems & the SaniDry.

 

[Brian H]

The only place that had animal intrusion was where the sanitary drain exits the crawl space and that has been sealed. The space is totally encapsulated and very dry .

I was just looking for a suggestion as to what I could apply, spray fog, etc to relieve the odor which I believe is coming from under the vapor barrier.

Thank you for all your suggestions.

 

[Desk Jockey]

Somebody always wants it easy.

Enzymes work best on urine. Apply it liberally so it can digest the bacteria. Better do it soon...winter is on her way.

 

[Brian H]

Somebody always wants it easy.

Enzymes work best on urine. Apply it liberally so it can digest the bacteria. Better do it soon...winter is on her way.

I's fully insulated. Even in the winter the crawl space is at least 55 degrees.

 

[Bob Pruitt]

Needs to be air flow.

 

[Old Coastie]

Ventilation is a mixed blessing. Capping the soil with black plastic is simple and reduces the evaporative moisture by 90%. In fact, it is so effective that a house can dry too quickly and walls can crack.
Crawlspace venting is often done with small grills or bricks set on edge, or the cheapest pieces of garbage available. You want vents to open and close on their own, to allow air flow or to save energy. Even in winter, when humidity levels are low, if the temperature rises during the day it is good to open the vents, closing them again when the temperature drops.

The best ones that I know of are made by this company. Lots of inferior copies. Ignore them.

What does this have to do with carpet cleaning? Damp crawlspaces attract vermin and wood rot. Both stink. Rising damp will make the carpets stink.

http://www.tempvents.com/index.htm