DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (http://www.diychatroom.com/)
-   General DIY Discussions (http://www.diychatroom.com/f2/)
-   -   Black mold on underside of plywood in addition.... (http://www.diychatroom.com/f2/black-mold-underside-plywood-addition-132931/)

tomwalla 02-07-2012 04:21 PM

Black mold on underside of plywood in addition....
 
I built an addition about 4 years ago on an existing old house. Where the addition was tied into the existing house, I had a water leak develop. I have since fixed the leak, but have had a real bad case of black mold develop on the underside of the plywood. It is not in every rafter bay but in the bays that it appears, it is well entrenched. I have plenty of ventilation in the attic with a gable vent, a ridge vent and 2 small vents on the side of the roof that has the bad mold. I should mention that the side of the roof with the mold has a very slight pitched shed type (2/12) roof coming off a 8/12 pitched roof. I don't have any bath fans that empty into the attic and have fairly good soffit venilation. I am assuming that the mold started when the roof was leaking and was so well developed that it didn't go away after i fixed the leak. What is the best way to get rid of the mold?

titanoman 02-07-2012 04:36 PM

Bleach.

Maintenance 6 02-07-2012 04:51 PM

If you've fixed the leak and everything is now dry, the mold has gone dormant. That doesn't mean dead. It will still emit particulates and spores. First get some plastic around the area, so that when you disturb it, it's not falling down into insulation and other parts of the building. Spray it down with a detergent solution. and scrub it off with a brush. Wear a respirator (N95 with P100 cartridges). After it has thoroughly dried, treat it with a fungicide. There are several out there. Quaternary amonias, Phenols and Bleach. Take your pick. They all kill mold. Bleach is cheapest and easiest to use. Whatever you pick, apply it with a garden sprayer. Let it completely dry. Apply a sealer to lock down any stray fragments. Kilz, Zinnser all make sealers. The bleach bashers will be along shortly to post links to all the "mold is gold" websites that tell you bleach won't kill mold, but that's BS. Don't fall for it. Just don't be inhaling a lot of bleach fumes.
Often, the water stains on plywood are not all mold, but just that, water stains.

Nailbags 02-07-2012 05:24 PM

A simple fix use Bleach to kill it. Now some things people think is black mold is tannin stains from the wood and nails from water. But just bleach it good let it dry well and your going to be ok.

Gmun396627 02-09-2012 10:26 AM

Hospitals USE !!!
 
9 parts water to 1 part bleach even kills the aids virus ! I use it on my molding then paint seal once it is dry ! Someone let me know if there is a better way

Geoerge

Nailbags 02-09-2012 12:55 PM

Quote:

Originally Posted by Gmun396627 (Post 848607)
9 parts water to 1 part bleach even kills the aids virus ! I use it on my molding then paint seal once it is dry ! Someone let me know if there is a better way

Geoerge

As long as you can smell the bleach it is good. I like using 8:1 ratio that kills the hep B virus that one is harder to kill then HIV.

Maintenance 6 02-10-2012 04:16 PM

Mold isn't bulletproof. 10% bleach will not only kill it, but will destroy the glucan bonds of the mold's cell walls and disolve the protiens inside to the point where they are not even considered allergens.* Just make sure you are well ventilated. Aerosolized bleach can easily form some nasty chloroform compounds that you don't want to be breathing.

* Actually concentrations as low as 2.8% have been shown to be effective with a 5 minute dwell time.

The AIDS virus is pretty fragile outside of a warm body. Common cold viruses are some of the toughest critters. That's one reason why they are so prolific.

Gary in WA 02-10-2012 04:33 PM

Usually the mold on plywood comes off easily because it is on the surface, as said. You may have difficulty with Doug-fir lumber (organic material) and bleach alone: http://ir.library.oregonstate.edu/xm...pdf?sequence=1

Gary

jasin 02-10-2012 04:39 PM

Bleach should never be used to kill mold, even though it does kill mold, or at least according to Osha it does. Here's why: The problem with Using bleach to kill mold is its corrosive. It can mess up, because it's corrosive, the integrity of whatever the mold is on when its used to kill mold. Only plastics and Glass can bleach be used on without it being corrosive because those materials are inert. In residential homes though mold is typically on things that are not made of plastic or glass. Also, you can't use it straight up as it is an irritant. It will make your skin itch and even feel like its burning your skin. So to make it less of an irritant it has to be diluted with water which reduces its concentration and as a result, its overall effectiveness.

jasin 02-10-2012 04:56 PM

Many often remove mold without remedying the situation. Preventing mold from coming back in the future. And that's a very BIG mistake.

Maintenance 6 02-11-2012 08:14 AM

It's interesting reading. I would love to know more about their test methods, like how did they isolate their test samples. I've read a number of these studies, but some make me wonder how valuable they are, especially when they have unexplained anomalies in their samples. Also notable that on the most common strains; the ones you'll likely find first on building components (aspergillius, penecillium), bleach was as effective as anything else.

Bleach should never ever be used straight for anything. And that is why OSHA has an interest. Some remediation companies were having workers use straight bleach as a fungicide which is dangerous to the workers health. Other than their mandate to protect workers, OSHA has no interest in killing mold. Pretty much the same with any EPA studies. Their mandate is to protect the environment from injurious chemicals and processes. Emitting chloroform compounds into the atmosphere is contrary to their mandate.

There is no reason to use bleach on hard surfaces such as plastic or glass. Those materials can be cleaned just as effectively with dish soap and save the chloroforms. The primary things to remember when cleaning up molds is that you first need to control the moisture that caused the problem. Otherwise your are wasting time. Second, it is not reasonable to think that any fungicide is going to penetrate porous surfaces and kill everything. That is why sealing the surface after treatment is important to lock down those mold components that cannot be reached. Hyphae/mycellium may become so deeply embedded in some porous surfaces that topical application of fungicides will not reach them. Without moisture control and sealing, those components will regenerate into fresh mold colonies. That is why some building components, such as drywall should just be replaced. The cleaning and treating time/cost versus effectiveness don't make sense. People tend to worry about spores, but spores are everywhere and are impossible to control and are opportunistic meaning they can float around until they can cling to a surface. There they will wait until conditions are right before blooming into a full fledged mold colony. Very, very few mold spores ever have that opportunity inside a structure.

1. dry it 2. clean it. 3. treat it. 4. seal it

jasin 02-11-2012 09:32 AM

Quote:

Originally Posted by Maintenance 6 (Post 850209)
It's interesting reading. I would love to know more about their test methods, like how did they isolate their test samples. I've read a number of these studies, but some make me wonder how valuable they are, especially when they have unexplained anomalies in their samples. Also notable that on the most common strains; the ones you'll likely find first on building components (aspergillius, penecillium), bleach was as effective as anything else.

Bleach should never ever be used straight for anything. And that is why OSHA has an interest. Some remediation companies were having workers use straight bleach as a fungicide which is dangerous to the workers health. Other than their mandate to protect workers, OSHA has no interest in killing mold. Pretty much the same with any EPA studies. Their mandate is to protect the environment from injurious chemicals and processes. Emitting chloroform compounds into the atmosphere is contrary to their mandate.

There is no reason to use bleach on hard surfaces such as plastic or glass. Those materials can be cleaned just as effectively with dish soap and save the chloroforms. The primary things to remember when cleaning up molds is that you first need to control the moisture that caused the problem. Otherwise your are wasting time. Second, it is not reasonable to think that any fungicide is going to penetrate porous surfaces and kill everything. That is why sealing the surface after treatment is important to lock down those mold components that cannot be reached. Hyphae/mycellium may become so deeply embedded in some porous surfaces that topical application of fungicides will not reach them. Without moisture control and sealing, those components will regenerate into fresh mold colonies. That is why some building components, such as drywall should just be replaced. The cleaning and treating time/cost versus effectiveness don't make sense. People tend to worry about spores, but spores are everywhere and are impossible to control and are opportunistic meaning they can float around until they can cling to a surface. There they will wait until conditions are right before blooming into a full fledged mold colony. Very, very few mold spores ever have that opportunity inside a structure.

1. dry it 2. clean it. 3. treat it. 4. seal it

Plastic shower curtains get mold on them very easily. But they are very thin, flexible, and pliable making them hard to scrub. You have to actually lay them flat to scrub them and still, even then, it does not go to well. Best way to clean them is not to scrub them but wash them in the washer machine with bleach. Also, I have heard its generally not recommend to scrub mold off as the mold spores can disperse, be breathed in, or stay on the object using to scrub it off.

Scottphys 02-11-2012 09:34 AM

Just posted this on another thread. Be careful with black mold.
Despite my dislike for the EPA, they do have good information about mold remediation. Check this out before proceeding and good luck!

http://iaq.supportportal.com/ics/sup...estionID=21163

jasin 02-11-2012 04:15 PM

Quote:

Originally Posted by Scottphys (Post 850255)
Despite my dislike for the EPA

:laughing:

Maintenance 6 02-11-2012 04:21 PM

The mold on shower curtains is living on soap scum. Soap is high in fatty acids which makes good mold food. When spores are dry they are easily dispersed. If you wet them before you scrub, it's not an issue.

As far as the EPA, keep in mind that they are not an authority on killing mold. Their job is protecting the environment.

There is a ton of mis-information on the interrnet about mold and health effects. Most is hype from "Magic Mold Potion" sellers trying to pitch some product that is basically a batch of chemicals you can find under your sink.


All times are GMT -5. The time now is 07:59 AM.