We bought a house about a month ago, and have just noticed some mold appearing in one of the closets. Upon further notice, it appears that the previous owners expanded/refurbished the closet.

I have been into the attic and the basement looking for probable signs of water leakage with nothing being obvious.

My question is: The closet is on an outside wall, with no insulation behind the drywall. Can condensation have caused the mold, or is it more probably a water leak from the roof, etc?

Thanks

With no insulation behind the drywall, condensation is a major suspect in the case. If you had a roof leak, you'd probably see stains in the wallboard somewhere. Before you tackle any major projects. I'd suggest the following:

You can buy mold-removing chemicals at paint stores or good hardware stores. The stuff is nasty, so use gloves and goggles, and make sure you have lots of ventilation. After the mold is removed, leave some space on that end of the closet, and hang an ordinary mechanic's drop light where the mold occurs, and see if it doesn't come back. Often, in a closet, the heat from an ordinary 75-watt bulb will be enough to prevent mold.

If the mold doesn't begin to return, then you know that condensation was guilty as charged, and you can think about ripping off the drywall and insulating that wall.

I agree with Richard, Very common for mold to develop in a exterior closet. Happens a lot where people use the closet to hang damp jackets and store wet shoes. Remove all the clothing within the closet and clean in the hottest water with detergent you can. for those items that cannot be cleaned take to the dry cleaner. Otherwise dispose of items that are suspected to have mold on them.
Wipe the entire interior down with a strong detergent. Dry the walls and leave ventilated. Once dry pick up some Zinsers oil based stain killer with Microban anti-microbial in it. The big box home centers carry this.
Once dry you can use again. Ideally you should consider insulation of the exterior wall.

As a retired Dry Cleaner and certified clothing restoration expert let me put my two cents in.

The only thing that will get rid of mold and mildew is a chlorine bleach solution. Ozoning with an ozone machine will kill the mold and mildew but it will not get rid of the stains.

If there are garments in the closet labeled "dry clean only" they may be wet cleanable but not be safe in a water-chlorine bleach solution. You will be wasting your money if you take them to a dry cleaner who CAN"T ozone them. The only thing that ozoning may damage is a rubber based textile such as the elastic in waistbands.

Check the integrity of the wall where the mold is growing. If it is soft, time to knock it out and replace the sheetrock. While you are doing that, cover the outside wall with plastic sheeting in between the studs and then put in some insulation. To just kill the mold is a waste of time unless you like cleaning it over again and again.
To kill the mold and leave wall as is, Zndust is right. Clorine Bleach, hot water mixed 25% bleach. Wear rubber cloved and use a scrub brush to scrub the mold off. This may remove paint and texture in the process.
We are in a closet, so just get yourself some 40 minute sheetrock mud and mix it loose. Take a paint brush and using just the tips of the brush, dab the sheetrock mud onto the wall. As you do this, turn the brush in circles. Or you can spend about $15.00 and buy a can of touch up orange peel texture. Doesn't cover a very large area, but is quick and easy.
If the area of damage to the wal is extensive, you may have to resurface the wall with a good scratch coat of drywall mud let it dry and then scrap it smooth with a drywall knife before you retexture it.
After the texture has dried, cover the whole wall in the area with Kilz primer paint with mold inhibitor in it. Then paint your normal color paint over it.
As I said before, it is a waste of time to clean the mold and repaint unless you first get insulation into the wall.
The lack of insulation within the wall is causing the mold. It gives it a great foothold in the wall and will continue to return unless you get rid of the cause, the cure will not take.
I remodel and repair daily.

By the way, anybody sick of the smell of paint? add just a teaspoon of pure vanilla extract per gallon of kilz interior exterior primer paint and the smell will be better.

Any time you are dealing with mold, it is essential that you wear a mask or ventilator. Air borne mold can be deadly. If you plan on removing sheetrock, wear the mask.

If you found mold on the back side of sheetrock where there is no insulation, the mold is because he backside of the sheetrock is where the air is reaching dewpoint, you will need to get rid of the mold through remediation or replacing the sheetrock. Then insulate properly to resolve the issue..preferably with a solidified cellulose insulation.. ie; Applegate cellulose.

First of all, lets look at the safe way to get rid of the mold. The old bleach trick works, but the dead mold spores can be as deadly as the live ones. I wouls strongly suggest if the area is small, to contain it with 6 mil medium poly,seal the area with tape, and remove the area completely. Always wear a N95 resperator and rubber gloves, mold can enter the body dermally.Once the affected area is gone, then try to find the source of water. Mold needs water, and food to survive. The paper on dry wall will feed mold. One you've corrected the water problem, the mold should not return. If you have any questions, please feel free to email me at www.ripbugs.com or go to the Indoor Air Quality Assn. for another professional in your area to help. www.iaqa.org good Luck.

quote:

cover the outside wall with plastic sheeting in between the studs and then put in some insulation

All good advice except for the statement quoted above, which is backwards advice and completely incorrect unless the house is in an extreme southern climate. Working from the inside, the insulation should go in first, and then, if the insulation does not have an integral vapor retarder, the plastic film should go directly on the inside face of the studs, before the wallboard goes on. Never never have two vapor retarders, and never place the vapor retarder anywhere but on the winter warm side of the wall assembly, again unless in extreme southern climate.

Thank you all for your responses. You have confirmed my first assumption. I went to the CDC website which suggested a bleach solution of 1 cup per US gallon, which I did. The mold came off very easily with little to no discolouration of the paint underneath. I suppose we caught it very early. We washed the walls down, have dried it out with a space heater (UV light space heater) and kept the door open ever since - et voila, no more mold. We are going to monitor the closet closely for the next week, and then make the decision on when/how to rip out the drywall and install insulation. Having framed a basement and walls previously, this should go quite quickly. And, yes, up here in the "north" the vapour barrier does go on the warm side.

Thank you all again.

I have mold on my ceilings. Twice, I have insulation blown into my attic, once in 1980's and the second time in 1997. Since then wherever the studs are it shows mold, also right where the ceiling and walls met there is mold about 2 feet across the ceiling in my kitchen. In the living room it goes all across the room. I need to know what is causing this problem. I have painted over the ceiling with Kilz's but now it is bleeding thru again. What can I do??

Larson, get a professional in to evaluate the cause and clear the mold out. Black mold, which tends to grow on the framing is very dangerous, and the spores will circulate throughout your house. Don't waste any time.

Wow! I have to wonder where some of the folks who post here have gotten their mold remediation expertise. In between all the mis-information there lies a few grains of truth. First, mildew is a misnomer. Mildew is a mold that grows on the leaves of living plants. Mildew will even live on mold in the right conditions. The stuff in your shower is either mold or bacteria. The stuff on your walls is mold. Second, "deadly" mold is deadly to whom? Every person who posted here just inhaled how many mold spores when they drew that last breath? The "deadly" part is a lot of media hype. Unless you have a compromised immune system from something like an organ transplant or cancer treatment or HIV disease, you are not likely to suffer any ill effects from exposure to mold spores. Persons who suffer from respiratory ailments may should limit their exposure as well. Persons who fit in the above catagories should not be exposed to mold, especially aspirgillus type molds (about 40 species, at last count). If you raked the leaves around your house or cut the grass, you were exposed to very high levels of mold spores. Want a real large dose? Spread tan bark or mulch around your shrubbery. Want a small dose? Sprinkle ranch drssing on your salad. All of these release mold spores into the air. Third, the recommended procedure to kill mold spores in healthcare settings, (where all of the vulnerable people are) is to use a 10 percent bleach solution. It has been proven to be as effective as anything else. DO NOT exceed 10 percent. Higher concentrations can have ill effects on the person using the material. Bleach solutions emit chlorine gas, so use them in a ventilated area. Hardly anything nasty or microscopic can live through a 10 percent bleach solution. A spray of bleach solution will kill the mold organism and spores, but you must clean up the dead carcasses. Mold components have been shown to be allergens to some people. Mold does require moisture and a food source to survive. My greater concern in finding mold would not be with any health effects (provided that none of the building occupants fit into the vulnerable catagory), but rather, the fact that if conditions are right for mold propagation, then they are right for doing serious damage to your building. Another thing to be cognicent of, is that mold colonies will send mycellia (roots) into an organic material to bring back food. These roots can remain embeeded in a porous surface even after cleaning just waiting to bring back a mold colony when conditions are right once again. That is why it is important to correct the condition that allowed the mold to grow in the first place. Finally, beware of the remediation "expert". Only one state in the country (Texas) has a standard for mold remediation professionals. The rest are regulated by no-one and many are educated by no-one either........ but since the mold thing has been hyped into a major concern by our over active media, lots of folks out there have jumped on the remediation bandwagon.

If your only seeing the lines of the studs on the ceiling your seeing condensation stains which is called ghosting. This is caused by the cooler studs on the ceiling allowing heat loss into the cooler area above. When this happen a small amount of condensation develops on those areas. Dust in the house. caused from cooking, burning candles, smoking etc. will stick to those cooler damp spots and the lines will develop. This is a vey common condition in homes with smokers. You may even see where the nails are long before the studs begin to show through.
Clean and repaint and check the insulation once again. Pehaps this area is not getting enough insulation because of its location in the attic and the contractor cannot get to it.
Although mold can develp if enough spores collect and the area stays damp long enough, the chances of developing this Black Mold is slim.
Even though you have had insulation blown into the space above, unless its covering the studs, and by several inches you will still get the thermal break because of the wood beams. I assume the stains are worse towards the exterior walls. That is where the attic is at its coolest point.

Follow the moisture stains...

Where do they run down?

If you see water stains coming from above, then it is a roof leak.