Investor · Knoxville, TN · Member since 2012 · 96 posts · 33 votes
I've read other threads on BP about mold, but as you know different regions of the country tend to experience mold in different forms and fashions. Here in the south, we have lots of crawl spaces that are very humid and the floor joists start to get growth. My present rehab has just that, but the boards are not rotted or moist, just surface "blackness" at this point. Because everyone wants to sell you something or not be liable for bad advice, its hard to get good solutions to these type issues. I don't really feel like I need to hire a mold outfit for such a light situation, but I don't want future problems either. I plan on getting better ventilation, replacing the insulation that has some growth, and replacing the insufficient vapor barrier. But can anyone offer a step by step process by which I can first get rid of the mold and then make sure it doesn't come back. The cleanup is what I'm mostly concerned about. After that I've been directed to Bora Care solution to treat the wood, but someone else suggested "20 Mule Borax soap". Thoughts on any of this......
Real Estate Investor · atlanta, GA · Member since 2013 · 456 posts · 237 votes
12y
When it comes to mold, there actually aren't a ton of ways to skin the cat. First step, identify your source of moisture. It is usually an even split between gutters, drainage and vapor barriers. Remove any debris or scrap wood from the space or any other food source for mold. While many are well intentioned, bleach absolutely doesn't kill the spores that cause mold & mildew. It will knock it down some but that's about it. Many make this mistake of cleaning with bleach or detergent and then paint the surface only to wonder why it is graying underneath. Mold is anaerobic so once you paint over it, you've given it a motel 6....perfect place to thrive.
Microban is the industry standard for treating, killing and cleaning mold. It is usually available at JonDon supply stores but you will need a commercial account. Treat the area thoroughly with Microban....then add adequate venting....a thick vapor barrier which we usually bring about 1' up the sides and seal off the edges. Mold spores can live dormant for millions of years...cleaning it with a brush & something like borax runs the risk of mold spores getting into the air and relocating elsewhere. I've heard of others using borax but I never have. Microban is more expensive but it kills on contact...no scrubbing just spray and you're done.
My favorite house to buy is the one with black mold....scares everyone else away and it's usually an easy fix. Happy Investing!
Residential Real Estate Broker · Kingman, AZ · Member since 2014 · 131 posts · 18 votes
12y
I think my husband just sprays bleach on the spot and scrapes it off... he did that with my moms house a year ago and it hasn't come back yet.. He does this for house preservations too.
Rental Property Investor · Greer, SC · Member since 2012 · 161 posts · 75 votes
12y
My first task would be to determine the cause of the excessive moisture. Have you determined if there is poor drainage, damaged guttering, moisture barrier etc.?
Developer · Decatur, GA · Member since 2011 · 1k+ posts · 1k+ votes
12y
1. Eliminate moisture
And clear out debris - drainage, leaks, etc
2. Prevent add'l moisture - dehudifier which drains to the outside, new vapor barrier 6 mil plastic one foot up wall tape with gorilla tape with overlap
3. Dish detergent and water wipe down of joists. (First or last)
Residential Real Estate Broker · Kingman, AZ · Member since 2014 · 131 posts · 18 votes
12y
Hubby says bleach kills it but you still need to spray stuff called Kilz on it... but you still need to find the source of it first so it wont do it again.
Investor · Knoxville, TN · Member since 2012 · 96 posts · 33 votes
12y
I've got a pretty good handle on the cause of moisture. Moisture barrier is shot, stupid crawl space dryer vent, no deck flashing, not enough vents....... That stuff is easily fixable. But getting rid of the stuff is what I'm interested in. Is dish soap really all I need to do?
Rental Property Investor · Denver, CO · Member since 2013 · 4k+ posts · 2k+ votes
12y
This is what they did to the place I bought that had mold and raw sewage sitting in it for a few months. They removed everything that wasn't structural, drywall and insulation. They pressure washed the remaining wood with hot water and an anti-bacterial agent (not sure what it was). They then treated (painted) the wood with an antibacterial paint (I think it was Microban or something like it).
Note removal was done with proper ventilation and protective clothing including respirator/mask designed to filter out mold.
Investor · Knoxville, TN · Member since 2012 · 96 posts · 33 votes
12y
Thanks for the input everyone. Seems apparent there are a lot of ways to skin a cat, but I think I've got a pretty good idea of what I need to do now. From what I'm hearing and what I've read, here is my list:
1. Fix any moisture/vent problems
2. Scrub with dish soap and or bleach
3. Spray with a borax solution (Roach Away is $3.00 and supposedly kills but also keeps from coming back.)
4. If feeling really ambitious or if it still looks ugly, paint with microban or similar.
Real Estate Investor · atlanta, GA · Member since 2013 · 456 posts · 237 votes
12y
When it comes to mold, there actually aren't a ton of ways to skin the cat. First step, identify your source of moisture. It is usually an even split between gutters, drainage and vapor barriers. Remove any debris or scrap wood from the space or any other food source for mold. While many are well intentioned, bleach absolutely doesn't kill the spores that cause mold & mildew. It will knock it down some but that's about it. Many make this mistake of cleaning with bleach or detergent and then paint the surface only to wonder why it is graying underneath. Mold is anaerobic so once you paint over it, you've given it a motel 6....perfect place to thrive.
Microban is the industry standard for treating, killing and cleaning mold. It is usually available at JonDon supply stores but you will need a commercial account. Treat the area thoroughly with Microban....then add adequate venting....a thick vapor barrier which we usually bring about 1' up the sides and seal off the edges. Mold spores can live dormant for millions of years...cleaning it with a brush & something like borax runs the risk of mold spores getting into the air and relocating elsewhere. I've heard of others using borax but I never have. Microban is more expensive but it kills on contact...no scrubbing just spray and you're done.
My favorite house to buy is the one with black mold....scares everyone else away and it's usually an easy fix. Happy Investing!
Severna Park, MD · Member since 2013 · 7k+ posts · 7k+ votes
12y
When using the bleach , add dish soap to the mix , it will give the bleach cling . Avoid spraying the solution on metal or electrical , it is a corrosive .
Investor · Carbondale, IL · Member since 2009 · 95 posts · 31 votes
12y
The source of moisture needs to be removed. You may need a sump pump to remove ground water. The remaining moisture, spores, etc is coming in from the vents. The warm air enters the cooler crawl space then condenses. Do you have moisture on water lines, joists, insulation, etc? For crawl space situations, I believe encapsulation is a solution. Basically seal up vents, install sump pump, install 12 mil+ vapor barrier(floor,up wall and around piers) and seal, install dehumidifier designed for crawl space(drains to sump). Also, I do believe the Bora care w/ mold treatment is a good product. I believe the humidity needs to be below 45% or so to prevent future mold growth, which is th purpose of the dehumidifier. There are companies that perform this work but is quite expensive. There are web sites with a lot of info, you can buy and do yourself. A lot of work, but much less expensive.
Developer · Decatur, GA · Member since 2011 · 1k+ posts · 1k+ votes
12y
Be ambitious on step 1 -- thoroughly eliminating the moisture problem for the next 20+ years. French drains, etc. may be required. I imagine Knoxville was very wet like Georgia. The moisture probably is a combination of the ground being saturated for much of the summer AND a drainage problem.
Cleaning - I think you have good ideas with bleach mixed with antibacterial dish soap OR microban. Like @Andy Luick said, you're not eliminating mold. You're killing a lot of it and eliminating the environment for its return.
For prevention - A professional in my area put 6 mil plastic down, sealed the vents, and installed a dehumidifier in the crawl space. If there's not high humidity, there won't be mold. You have to do a great job of step 1 for this expense to be worthwhile.
I've heard Kilz is used only for resale purposes. If you're flipping, mold was disclosed, joists or whatever is discolored (still scary to a laymen), then painting it with Kilz will reduce buyers' fear.
Real Estate Investor · atlanta, GA · Member since 2013 · 456 posts · 237 votes
12y
Every property that we take over in metro atlanta, if it's been vacant for quite a while, we treat every surface with Microban prior to painting. We're doing that now on one we are renovating for shared housing. It's just an added precaution for us that we have learned to take over the years. We sell most of these homes to passive investors and include a 1-year warranty on all repairs. Mold is a really serious issue in our market. I would be concerned about completely sealing in a crawlspace. Many of our older atlanta homes were built on piers with open spaces under the homes for storage and ventilation. Most of these have been closed or bricked in over the years and caused mold problems & dry rotting because the houses can't breathe anymore. Carefully assessing and addressing drainage & gutter issues will solve 75% of your problems, using a thick vapor barrier on dirt crawlspaces and making sure you have adequate ventilation will take care of the most of the rest. If you take away the moisture your mold will go dormant and only flash again if the moisture or humidity returns.
Real Estate Investor · atlanta, GA · Member since 2013 · 456 posts · 237 votes
12y
@Rick Baggenstoss - it will if the area has been properly treated with Microban first. Microban has a residual killing effect....kind of like Raid bug spray...it kills mold on contact and will continue to kill new mold spores that come into the treated area. I just personally never like to seal up ventilation...on the problem crawlspaces I work on through my contracting company, I am usually adding vents. We do a ton of water remediation work and the mold clean-ups that come with it and it absolutely amazes me the bids I see from my competitors....most never really address the source of moisture at all just overkill it with expensive systems and treatments. We did one in alpharetta last year where the owner had bids of $25k to $35k for clean-up and treatment. We came in and did everything for about $8k and are going back this spring to address some drainage issues for the homeowners which should run about $2,500.
The old time builders had it down pretty good. Mold scares most but those are my favorite buys as an investor...either on my own or with my group investors....great deals if you know how to handle it.
When it comes to mold, there actually aren't a ton of ways to skin the cat. First step, identify your source of moisture. It is usually an even split between gutters, drainage and vapor barriers. Remove any debris or scrap wood from the space or any other food source for mold. While many are well intentioned, bleach absolutely doesn't kill the spores that cause mold & mildew. It will knock it down some but that's about it. Many make this mistake of cleaning with bleach or detergent and then paint the surface only to wonder why it is graying underneath. Mold is anaerobic so once you paint over it, you've given it a motel 6....perfect place to thrive.
Microban is the industry standard for treating, killing and cleaning mold. It is usually available at JonDon supply stores but you will need a commercial account. Treat the area thoroughly with Microban....then add adequate venting....a thick vapor barrier which we usually bring about 1' up the sides and seal off the edges. Mold spores can live dormant for millions of years...cleaning it with a brush & something like borax runs the risk of mold spores getting into the air and relocating elsewhere. I've heard of others using borax but I never have. Microban is more expensive but it kills on contact...no scrubbing just spray and you're done.
My favorite house to buy is the one with black mold....scares everyone else away and it's usually an easy fix. Happy Investing!
Ditto that @Andy luck!
You can also use concrete to encapsulate the ground in a crawl space and then install a sub slab depressurization system, aka radon abatement fan. Be sure to put at least a 6mil vapor barrier under the concrete. Use rigid foam board polustyrene insulation as well for added benefits.
Real Estate Investor · atlanta, GA · Member since 2013 · 456 posts · 237 votes
12y
@Account Closed - go info - hadn't ever had to go to that length. It's little known, but we do have a bit of a problem with radon gas in the metro atlanta area. A lot of the homes I buy have had broken pipes when they didn't get winterized so we deal with the resultant mold pretty much every week. I pulled a sink vanity away from the wall on a house we are working on right now and it's entirely black with mold even though the walls themselves had very little mold. Head to get more Microban to treat it in a little bit!
Anytime we buy a house that has been sitting without a/c in our market, we clean and treat everything with Microban....just to be on the safe side prior to repainting. Great share!
House Flipper · East Stroudsburg, PA · Member since 2013 · 1k+ posts · 205 votes
12y
@andy @stevei are right. In my area many people use heavy duty peroxide as well. Don't forget the facemask. Most avoid spraying as it distributes the mold spores. The vapor barrier is a must and you might think of installing fans to dry out some of the moisture
Investor · Knoxville, TN · Member since 2012 · 96 posts · 33 votes
12y
Thanks guys for all the input on this one. Here in TN we are accustomed to a little mold. If you have a neighborhood with 10 houses on crawl spaces, 8 of them will have a little of the black stuff on the beams. I know in my primary residence I installed a couple of vent fans that kick on in higher humidity and I've not had any issues thus far. As for the property in question, it is all neglect issues that have led to a few isolated areas. It was a widow's home whose crawlspace dryer vent was loose, the moisture barrier was only partial coverage, the deck wasn't flashed, and the downspouts were neglected. I'm certain there isn't a moisture problem outside of those issues. So fixing the underlying problem is easy, but the nature of my question was just to that I cleaned up what was already there in an appropriate way. You have given me great suggestions and thoughts and I really appreciate it.
Elizabeth City, NC · Member since 2016 · 1 post · 2 votes
10y
The black and/or brown spots are often called "Pepper Mold", but in reality are a fungus. You can wipe it off all you want, but if the moisture level isn't controlled (below 20% Wood Moisture Content (WMC), it will simply grow back in larger numbers and locations. This is called a Non-Decay Fungus (NDF) as, in its current state, does not cause damage to wood.
Another type of growth that you should be concerned about is called WDF, or Wood Destroying Fungi. It usually starts out white in color but may be green or yellow. This fungi can be found when the WMC is 28% or higher, and is just as devastating to the integrity of wood as termites. Often times dry rot, cubicle rot, etc., can accompany this fungi.
The best resolve (assuming you don't have water actually flooding into the crawl) is a strong Vapor Barrier (at least 8-mil thick), spiked down and all seams taped. This should also run up the sidewalls no closer than 4" from the sill plate (to allow for termite inspections). Once installed, place a good commercial dehumidifier (preferably ducted) off-center in the crawlspace, with the collected water (moisture) being pumped outside the foundation walls.
As far as "cleaning" existing fungi, do NOT use bleach - chlorine dries out the wood and can be more damaging! In fact, don't waste the time wiping it off at all - If you follow the above steps with a vapor barrier and dehumidifier, monitor the WMC to ensure it's somewhere between 13% - 18%. If your moisture drops to this range, the existing fungi becomes dormant and cannot continue to grow. There are disinfectants (such as Benefect) that can be used to sterilize the existing fungi (as well as any dead rodents and their droppings, etc.).
The use of fans in a crawlspace is old-school and stopped applying 30 years ago. Fans will only circulate hot, humid air into a cooler, drier crawlspace, creating condensation and causing pipes and ductwork to sweat - you're simply adding more moisture!
Seal the vents closed - use 1/4" foam sheeting (cut over-sized) and place the foam over the foundation vents in the crawlspace and use a foam adhesive to adhere the pieces to the foundation wall. Close the vents. (If you have automatic vents, use a self-tapping screw to screw the metal flaps of the vent together, preventing them from opening. Check your local code requirements if you're in a flood zone.
Broken dryer vents, leaking pipes, standing water... These will all contribute to high moisture and should be checked for at least twice a year. Downspouts should be directed away from the foundation at least 4-5 feet with some type of extension (splash blocks, extra piece of downspout, etc.).
Investor · Northeast, NE · Member since 2015 · 258 posts · 83 votes
10y
Just going to throw this out there if the situation warrents these actions.
AGEED with all others as getting rid of moisture.
Have heard another method of getting rid of mold is to media blast using dry ice pellets as a media. First you spread a plastic throw away sheet down, blast it off unwanted surfaces,,letting the dry ice drag it down to floor plastic,,,, let dry ice evaporate,,,carefully wrap plastic to center and toss,,,protective gear should always be used. dry ice is hard on the skin so dont contact,,,cover up.
Rental Property Investor · Douglas County, MO · Member since 2014 · 1k+ posts · 1k+ votes
10y
I know this is an old thread, but reading so many posts that recommend mixing bleach and liquid dish detergent made me cringe. Dish soap usually contains ammonia, and should not be mixed with bleach. If you need to add soap to bleach use liquid laundry detergent.
I know this is an old thread, but reading so many posts that recommend mixing bleach and liquid dish detergent made me cringe. Dish soap usually contains ammonia, and should not be mixed with bleach. If you need to add soap to bleach use liquid laundry detergent.
dont know what dish soap you use , but I have been doing it for years ,I am not dead yet