Replies

1. 
   VAVince | Feb 05, 2006 04:11am | #1

   Looks like jungle rot.  Just joking. Man that stuff grows fast down there.

2. 
   BillBrennen | Feb 05, 2006 04:50am | #2

   Copper-based preservatives are very effective against all fungi. You sound like you need something that won't wash off with more rain. Given the speed with which the OSB grew those 'shrooms, I have to say OSB = bad for exposed structures in tropics. This is why the tropical hardwoods are mostly durable. They HAVE to be!

   Bill

   edited for spelling

   
   

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   Edited 2/5/2006 2:09 am by BillBrennen

3. 
   DanH | Feb 05, 2006 05:11am | #3

   There is a slight possibility (can't tell from the pictures) that what you're seeing is simply excess glue being carried out of the OSB (kind of like efflorescence on concrete).

   If it is fungus, bleach will probably kill it for now (maybe 1 part FRESH bleach to 4 parts water -- you'll be able to tell immediately if it's working), but you need a way to control it, and that means some type of preservative.

   Probably any sort of available wood preservative will work -- arsenic, copper, borate, etc. Just pick the nastiest one you're comfortable using. I'd guess your "corner hardware store" would carry whatever seems to work down there.

   It won't hurt to bleach it now (probably better when wet, in fact). Re the preservative, it depends on whether it's water-borne or not. Any water-borne preservative should still be effective when applied to damp surfaces. Solvent-borne preservatives should be applied when dry.

   If ignorance is bliss why aren't more people

   happy?

1. 
   mccarty12 | Feb 05, 2006 12:32pm | #4

   Thanks to you and everyone else for your responses. The thing that is strange is that the OSB is supposed to be treated with CCA. It is supposed to be in the glue. It is guaranteed againt termites for 10 years. Can fungi grow on wood treated with CCA?

4. 
   rjw | Feb 05, 2006 04:03pm | #5

   >>I have an online membership to JLC and in an article the author said that just soap and water would clean up the fungi. I always thought that bleach was to be used. In fact I'm pretty sure I read that in a US Forest Products publication.

   Over the past several years ,the expert sites have been pretty much abandoning the idea of bleach, I suspect because of the risks of people breathing bleach particles if they spray it and fumes if they don't handle it right, and reportedly it does no better than a good detergent in cleaning mold

   Bleach is nasty stuff, especially when inhaled.

   ---

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   Sojourners: Christians for Justice and Peace

1. 
   DanH | Feb 05, 2006 04:55pm | #6

   Yes, but bleach will denature anything organic and kill it good. Soap/detergent will kill some stuff, but nowhere near 100%.

   If ignorance is bliss why aren't more people

   happy?

1. 
   rjw | Feb 05, 2006 05:16pm | #7

   >>Yes, but bleach will denature anything organic and kill it good. Soap/detergent will kill some stuff, but nowhere near 100%.I don't claim to be an expert, but (i) the several courses and seminars I have taken on the subject say that bleach doesn't kill mold _spores_ (they need to be physically removed through scrubbing) and (ii) as I said, the experts have moved away from advising use of bleach in mold and fungus cleanup.As a general rule, I generally take the advice of experts (after consideration, of course.)And never forget, bleach can be dangerous to people

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   Sojourners: Christians for Justice and Peace

1. 
   DanH | Feb 05, 2006 07:05pm | #8

   Bleach CAN be dangerous if used carelessly, but in general is realtively safe. One should avoid getting the spray on yourself or others, but small amounts will cause no more than minor skin irritation (usually not even that) for most people. Small amounts inhaled or coming in contact with mouth, eyes, etc are rapidly diluted by mucous/saliva/tears. And the stuff is quite "biodegradeable", losing it's toxicity within an hour or so once sprayed.It's certainly orders of magnitude safer than, eg, a CCA wood preservative that one might find in Brazil.True, it may not kill all spores, but it's effective against virtually all actively growing organisms.

   If ignorance is bliss why aren't more people

   happy?

1. 
   rjw | Feb 05, 2006 08:48pm | #9

   This has been educational - I try to follow the changes in this area and it has been awhile since I dug in.There is a lot more cleanup information available now than even a year ago.There is no universally accepted answer on the use of bleach for mold clean up; most expert sites I read either advise against it or just don't mention it (at least directly.)Having looked today at 10-15 sites, it seems to me that bleach is still low on the list of recommended approaches ; some sites specifically recommend against it, some seem to but use the terms like "gaseous or vapor-phase biocides" which I _think_ mean sprayed bleach, some recommend it alone, some recommend it but only after other cleanup methods. And I know from experience that sites such as the EPA's and the NYC's cleanup sites have stopped recommending bleach.The majority of expert sites now recommend detergents and scrubbing/cleaning.But I'm always interested in learning more: as a home inspector I face potential liability if I give bad advice, esp on a litigious area such as mold.And I'm not trying to turn this into a nit-picking debate, but there a lot a people who will potentially be reading this thread for advice on mold cleanup.If you have any authoritative sources (in addition to the mentions below) recommending bleach, please let me knowSome specifics:Here's one tidbit from the EPA:"The purpose of mold remediation is to remove the mold to prevent human exposure and damage to building materials and furnishings. It is necessary to clean up mold contamination, not just to kill the mold. Dead mold is still allergenic, and some dead molds are potentially toxic. The use of a biocide, such as chlorine bleach, is not recommended as a routine practice during mold remediation, ...." [Exceptions follow]
   http://www.epa.gov/mold/i-e-r.html****
   Although this following EPA page is for commercial and school cleanup, its recommendations are not inappropriate for residential cleanup consideration:http://www.epa.gov/mold/table2.htmlIt does not include bleach as a cleanup method. ****
   Now, there is this abstract from 2005 on the internet from the American Industrial Hygiene Association which says bleach can help/work:106
   EFFICACY OF CHLORINE BLEACH IN KILLING AND BLOCKING ALLERGIC REACTIONS TO MOLD ON CONTAMINATED BUILDING MATERIALS.J. Martyny, K. Pacheco, R. Harbeck, E. Barker, M. Sills, S. Arbuckle, L. Newman, National Jewish Medical and Research Center, Denver, CO.The use of disinfectants for mold remediation has been discouraged, since simply killing mold has not been proven to reduce the antigenicity of mold spores. In addition, the ability of disinfectants to kill mold on contaminated environmental surfaces has been in question. We tested the hypothesis that the spray application of a dilute sodium hypochlorite solution on environmental surfaces will kill mold and significantly reduce mold antigenicity and allergenicity.
   . . . .
   We found that the application of either sodium hypochlorite solution or Tilex resulted in significant killing of Aspergillus fumigatus mold on the environmental surfaces, and produced observable changes in the appearance of conidia. .... The use of sodium hypochlorite solutions in mold remediation projects may therefore be beneficial.http://www.aiha.org/abs05/po114.htmNote that it doesn't say it is the best or recommended, just that it "may be benefical"(Note also that page has abstracts about a lot of mold and construction issues, including "lumberyard mold.")****
   Compare that to to this older report from the same site:http://www.aiha.org/committees/html/iac/AIHA%20Microbial%20Growth%20Task%20Force%20Report.pdfThe on-line pdf at that page limits cutting and pasting, but if you search the document for the word "bleach" you will find a number of negatives and some teprid positives on the use of bleach.****
   A "pro-bleach" article: http://www.ascr.org/news/flood_repair_guide.pdf
   © 2005, ASCR International. Reprinting and distribution with credit is permitted. (The Association of Specialists in Cleaning and Restoration, Inc. (ASCR))Decontamination
   ß Hose down mud and silt, mop or squeegee dry.
   ß Clean moldy surfaces with a HEPA-vacuum, if available.
   ß Wash all affected surfaces with a combination cleaner-disinfectant if available, or with household
   detergent and water, using a scrub brush or scraper for stubborn stains.
   ß Saturate contaminated surfaces with a disinfectant cleaner or bleach solution (1 part bleach to 9 parts
   water) and keep wet for at least 10 minutes. (Caution: do not use bleach with ammonia or ammoniated
   detergents!)Note: however, the same organizations page on "best practices recommends deterhgents and warns: "The use of gaseous or vapor-phase biocides for remedial purposes is not recommended."Question: does that mean bleach from a spray bottle?
   http://www.ascr.org/masterdocs/documents/mold_bestpractices.pdf****
   Here's a state site which recommends bleach but only after scrubbing with detergents etc:# First, wet the moldy area down by spraying lightly with a water-and-detergent solution to help keep mold dust and spores from getting into the air. A high-efficiency particulate air-filtered (HEPA) vacuum cleaner can also be used to help in removing surface mold growth and removing the spores from nearby materials.
   # Using a non-ammonia soap or detergent and hot water or commercial cleaner, thoroughly scrub all moldy surfaces.
   # Rinse the scrubbed surfaces with clean water. A wet-dry vacuum may be used to collect excessive water.
   # After cleaning, a disinfectant solution such as household bleach and water (¼ to 1½ cup liquid chlorine bleach to one gallon of water), can be applied to the affected surface. Never mix bleach with ammonia - toxic gases can be created. Follow all label directions on all products used in this step. Make sure the area is well-ventilated when using disinfectant solutions. For this step to be most effective, the disinfectant solution should be allowed to stay on the surface for 6 to 8 hours and the solution should be allowed to dry naturally.http://www.epi.state.nc.us/epi/oii/mold/nonporous.html****
   Another pro-bleach: but note the safety conditions/details:"Use bleach to clean mold off hard things (like floors, stoves, sinks, certain toys, countertops, flatware, plates, and tools).
   Follow these steps:
   Never mix bleach with ammonia or other
   cleaners.
   Wear rubber boots, rubber gloves, goggles,
   and N-95 mask.
   Open windows and doors to get fresh air
   when you use bleach.
   Mix 1 cup of bleach in 1 gallon of water.
   Wash the item with the bleach and water
   mixture.
   If the surface of the item is rough, scrub the
   surface with a stiff brush.
   Rinse the item with clean water.
   Dry the item or leave it out to dry.http://www.bt.cdc.gov/disasters/pdf/flyer-get-rid-of-mold.pdf*****
   Another site which recommends detergents, but adds precautions to use if using bleach:
   http://www.ncsu.edu/ehs/www99/right/handsMan/air_qual/mold_remediation.htm

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   Sojourners: Christians for Justice and Peace

2. 
   rjw | Feb 05, 2006 08:59pm | #10

   For those who don't want to read thru all that stuff:There are no clear answers - the following is based on what I consider to be the current best informed information out there.My personal conclusion after (i) several courses (ii) many hours of internet research (in the past and today) and (iii) taking into consideration my professional interest/concern for liability because I give advise on these sorts of issues:(This conclusion also takes into account the potential for liability regardless of the merits of any given case.)Small areas (less than a 4'x8' area or less than 10 sq ft - take your pick) non-porous stuff: scrub/clean with detergent (automatic dishwashing detergent is my detergent of choice) and follow with a rinse with dilute (no more than 1:10 bleach:water solution using "suitable" respiratory protection and gloves(I'd also do that, say a large foundation area which is relatively accessible)Porous stuff of any size: tear it out and replace it. (Including the fungal growth on the OSB which started this thread.)If working for hire: Any job of any significant size (you decide what's "significant") get an industrial hygienist or other expert to dictate the plan and procedures and do what they tell you to do, and only after checking with your liability carrier as to coverage.

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5. 
   mccarty12 | Feb 05, 2006 09:32pm | #11

   I just want t o say thanks for all the discussion. This is exactly whay I was hoping for. I've always used bleach to kill mold but last summer ( in WI) I got a bunch in my eye when I was cleaning some mildew off a porch ceiling. When I read the JLC article I was a little confused because the author said that bleach didn't do much. I distinctly remember a book that I read from the Forrest Products Lab last year, when I had a mold problem on a deck, that bleach killed mold on contact. I'm going to call the people at forrest products tommorow.

   By the way, the JLC article that disrecommended ( if I made up this word so be it) bleach ,was by Doug Garrett in the June 2003 issue.

   Keep on talking.

1. 
   MarkH | Feb 06, 2006 04:09am | #12

   I can't say too much about this procedure, but saturating the osb with a saturated copper sulphate solution should kill all fungus. Copper sulphate crystals are use to kill roots in drainage pipes.  I would not get this stuff on your skin.

   http://www.copper.org/applications/compounds/copper_sulfate02.html

1. 
   DanH | Feb 06, 2006 04:30am | #13

   I'd like to point folks back to my first statement: Is it possible that this "fungus" is just chemicals coming out of the treated OSB? The pictures are poor, but the location and appearance of the "fungus" suggests this.

   If ignorance is bliss why aren't more people

   happy?

1. 
   MarkH | Feb 06, 2006 04:56am | #14

   It's possible.