Mold in Crawl

I have a damp crawl space that was encapsulated by the prior owner just before sale. It has a strong odor and humidity of 80-90%. I've just added a dehumidifier, but there are some small patches of mold on the plastic of the crawl that have developed this year. Can this be identified by photo as a concern, or will lowering the humidity and a clean with bleach be sufficient?
mold in crawlspace, cleaning tips, home maintenance repairs
mold in crawlspace, cleaning tips, home maintenance repairs
mold in crawlspace, cleaning tips, home maintenance repairs
mold in crawlspace, cleaning tips, home maintenance repairs
  22 answers
  • Adrianne C Adrianne C on Aug 14, 2014
    Clean it definitely, but try to ascertain where the water would be coming from. A leak perhaps?
  • Jeanette S Jeanette S on Aug 14, 2014
    It sounds to me that you need to open up that crawl space for ventilation. I don't know who came up with the idea of putting plastic under houses! I think that is a new trick to hide things! The underside of the house should get plenty of air! Hiding wet under plastic is not fixing the problem...there is either a leak somewhere or ground water is seeping in...either way, needs to be fixed!
    • See 1 previous
    • Jeanette S Jeanette S on Aug 15, 2014
      @White Oak Studio Designs True, but in this case it is not proving to be stopping the mold! If you will notice, the mold is "on top of the plastic" so it is still growing! I mentioned that the cause for the mold needs to be taken care of. If the space is damp, a professional needs to be called to find out why! Put in drainage around foundation??? Put in vents??? Find and fix leaks???? Install vent fans???? Trying to deal with it yourself can kill you if you do not have the proper protective gear to wear!
  • Tyrenta Tyrenta on Aug 14, 2014
    How can I get this thread moved to Home Maintenance & Repairs? There is no visible water only humidity and from what I can see this is the only visible dark colored mold in the crawl space (though there is a strong musty/urine smell). My main concern is if this mold appears to be standard mold that can be cleaned, or if it appears to be the more dangerous variety and I should call in a pro environmental service and pay thousands for their cleaning services (which they will recommend no matter what).
  • Trac Trac on Aug 14, 2014
    I live in the North Georgia Mtn's and we have very high humidity and very damp homes. We use to have a very moldy basement and my husband discoverd a product that was developed by the military and is safe for both humans and pets. It's a Broad Spectrum Virucidal, bactericidal and fungicidal disinfectant.You can purchase it on Amazon and it reasonably priced. Good luck
  • Tyrenta Tyrenta on Aug 14, 2014
    Some more info -- doesn't appear to be Stachybotrys from the Healthful Home test I had. And I found where outside air is leaking into the crawl for humidity issues. But I'm still concerned over the odor it's terrible, despite no visible mold issue outside of these few small patches.
  • Michelle Thorburn Michelle Thorburn on Aug 15, 2014
    Mould spores need to be killed and removed. A solution of 1/4 tsp of Oil of Clove to 1lt of water sprayed onto the areas left for 24 hours and then wiped over. Repeat if necessary.
  • Linda Linda on Aug 15, 2014
    As Jeanette said, why is there a plastic/linoleum lining in your crawl space? It should be dirt.
  • White Oak Studio Designs White Oak Studio Designs on Aug 15, 2014
    We dealt with flooding and crawl space issues, so I know exactly what you are dealing with. If that space was encapsulated (as it has to be by law to sell it) then you need to call that company to come back and complete the job. Something has gone wrong and you have a leak somewhere. the LAST thing you want is more water in the space. Don't wait get a professional in and have that taken care of.
  • Pamela Miller Pamela Miller on Aug 15, 2014
    I had a friend that had a similar problem and it was rat urine. The smell is awful and the humidity seems to carry it/make it worse. She had an exterminator come in and they also cleaned it out. Her's was worse than yours. They took out all the plastic. Usually there would be some dropiings though and don't see any in your picture.
  • Mssmatch Mssmatch on Aug 15, 2014
    My crawl space has plastic sheeting over all the dirt- is this ok?
  • Kathleen Turner Kathleen Turner on Aug 15, 2014
    You really should have a professional company look at that. Looks like black mold. It causes cancer! Be careful.
  • Carmen Carmen on Aug 15, 2014
    Mold can be dangerous and costly. I exhort you to have checked by a professional, and do not attempt to remove the plastic yourself,as it may spread.
  • Rrs368534 Rrs368534 on Aug 15, 2014
    I agree with Carmen. Do not try to clean yourself or use bleach. This is a health & safety issue. Get professional & licensed mold inspector to check this out.
  • DORLIS DORLIS on Aug 15, 2014
  • Tyrenta Tyrenta on Aug 15, 2014
    thanks for the responses. I had a professional environmental specialist out last year, and he said it was fine and didn't even need an air quality test which would be a waste of money. The professional humidity control firm that I bought my dehumidifier for my main basement from said the smell was strange -- more like cat urine than mold. The HVAC guy said we needed a duct based U/V air scrubber that of course he'd be happy to install. The basement systems firm that did the original install was happy to recommend additional services that they provide. They originally put down a vapor barrier, but it isn't air tight to the ground (they use plastic spikes to hold it to the wall). I can take a pretty good guess what a mold cleaning firm will recommend if I call them in for a hefty fee, actually needed or not. I did a mold test last night and it isn't black mold. I've seen several reports that soil off gassing can cause a strong urine smell in a small percentage of encapsulated basements, but I'd like to be sure that is the issue before going down that route. There were mice and reports that the prior owners had a rat problem at one point as well. I've been trying to solve these issues for almost a year -- the humidity I think I've finally solved but the odor is a nightmare.
    • @Tyrenta Your example is exactly what occurs on a daily basis. Companies come in to attempt to solve an issue that they simply do not understand. Snake oil salesman I like to call them. Moisture control is always the best method of controlling odors. Moisture is needed for the molds and outgassing to take effect. The U/V air scrubber will kill bacterial materials in the air, and will have a tendency to sweeten the smell, much like after a hard rain the air smells fresh. But that only fixes the results of the issue. Not the issue itself. A dehumidifier will help, but if the crawl space is properly sealed and done, the dehumidifier is not needed. As moisture cannot travel through the properly sealed crawl. There are several types of these units. But basically two methods that are used. One is mechanical dehumidification where there is a large AC type unit that sits on the ground that collects water in a pan or drains it down a tube. These units work well, but need to be properly sized and serviced. The 2nd system is a fan that pulls air from the basement/crawl area and dumps it outside. Wave makes a pretty popular unit that works in this manner. These systems, both the fan and mechanical method works well, with the fan system making the air smell better, but neither does anything to solve the issue why your area is damp. The mold test told you nothing. I assume you used a petri dish test that you purchased from a home center? The Black mold you are speaking of really only grows on paper products. So it would be a surprise if you found it. Mice and rat infestation can cause odors but you need a pretty tight area and lots of rodents, unless they die to create foul odors in the home. But if the space was properly sealed from the start, the likelihood of having these critters are pretty slim. To properly solve the issue is to determine where the moisture is coming from. If its simply dampness from the soils in the crawl, then look at the outside to determine why the soil is damp. Are there a lot of trees and shrubs around the area? Is the gutters clean and piped at least six feet away from the foundation? Is the soil pitched away from the house? What about in ground sprinkler systems? Are they hitting the house? All of these contribute to moisture in the crawl. If you have an adjoining basement with a sump pump pit, is the pump running all the time, or does it contain some water but never really fills until there is a rain? The latter indicates a low water table. And your crawl area is much higher so the dampness is not coming up from the ground below. To solve this is to understand the source of the dampness. Some ground will tend to remain damp for many reasons that are unknown without really looking at the remaining conditions. Even a poorly air sealed house in the attic will cause damp rising to occur in the crawl spaces below. A properly installed vinyl liner up on the sides of the crawl space to the sill area will stop moisture and odors. Its often difficult to do, but if done properly it solves all sorts of issues.
  • The mildew your seeing was caused by standing water and the associated dust that collected. It appears that the vinyl that was used to cover the floor was a vinyl floor remnant that was placed down on the ground. An admiral idea, but horrible use of such a product. 1st. the mold you see is easy to simply clean up using any quality shower and bath cleaner. The material that is allowing this to grow will not really support any real nasty stuff. But if you do suffer from mold allergies or have someone in the home that does, or even a compromised immune system you will want to wear a mask and soak the area down before attempting to wipe it away. Or get someone else to do the cleaning for you. The 2nd thing you need to understand is that its very likely there is a real mold concern below this vinyl material. Vinyl flooring is a mix of sorts. It has a plastic type top where the pattern is placed, then under that there is a material that is more like a paper product. Normally this the material that the glue sticks to when fastening the floor down. In fact if you ever tried to pull up a vinyl floor after it was glued down, this is the material that remains as the surface pulls away. In any case, this material is a paper product. Paper is ideal food for mold development. The moisture that was part of the issue why the vinyl was placed down is the amount of dampness mold needs to develop. You will need to remove this covering. This is the strong odors that your are smelling. The proper way to seal the crawl area is to rake any organic materials out from that area. Then using a vinyl sheet, much like a pool liner place that down and up the sides of the crawl space. To at least six or 10 inches above the outside grade. Ideally the vinyl should extend to the wood sill, but not cover it. All seams need to be sealed. Vinyl glue should be used. Just be sure the area is well ventilated. Seams can also be taped using vinyl tape designed to use with the product your using. Many people use plastic that they purchase from the home centers. This will work, but its short lived as over time this material will begin to crack and fail. The vinyl material will last a much longer time and resists damage should you need to move around in there for services or storage.
    • See 1 previous
    • Bonnie Bonnie on Aug 18, 2014
      @Tyrenta I concur with Woodbridge, sound advise. I own a professional cleaning company and we have dealt with many types of issues. I am wondering, however, if this isn't more of a bacterial problem than mold... I would like to caution you about using your dehumidifier while this problem exists; it will be taking in the spores or bacteria as it does the moisture vapors. Make sure you wear a mask if you are going to be anywhere near it. You will continue to have a problem until the source of the wetness is located and repaired. Your testing kit should be showing signs of growth by the 3rd day, but you should allow 5 days.
  • Charlotte Belange Charlotte Belange on Aug 15, 2014
    were ever it is just cut it out you may have more mold than you think
  • Irish53 Irish53 on Aug 15, 2014
    Have you tried Damp rid? They have all styles for different ares of the house works great. I have used an open bag of charcoal with out the lighter fluid to clear up orders in the basement should also work in crawl space.
  • Jaci Jaci on Aug 15, 2014
    Try white vinegar instead of bleach. Easier on the lungs and will help neutralize odor, especially if it is animal urine
  • Linda Linda on Aug 16, 2014
    OK, I had no idea that we didn't do dirt crawl spaces anymore. Or maybe the regs are different from state to state?
    • See 1 previous
    • Linda Linda on Aug 17, 2014
      @Woodbridge Environmental Thank you for the explanation! Very nicely stated.
  • Rrs368534 Rrs368534 on Aug 16, 2014
    You made the right choice by getting professional looking at it.
  • Susan H Dittman Susan H Dittman on Aug 16, 2014
    Bleach only appears to get rid of the mold. It is the spores that are so hazardous and bleach does not kill them. I am just now reading the most recent posts here and it looks like you got professional help. Good choice!! Mold is dangerous. Read about it in Leviticus 14:33-53
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