Killing mold

[Sam Murdoch]

Situation existing is contaminated drywall around some windows and below some skylights that have leaked in the past.

Result is some type of white mold bloom - a powdery white organic substance - growing around some cracks in the corners of the window returns and other places. I've been told that this drywall (wet wall really) has been replaced in the past but the mold continues. Doesn't seem to spread (or if so very slowly) just covers an 3" or 4" area in some creases and corners and literally blooms out in a white fluff.

I know for a fact that the leaks have been stopped so I'm guessing that the mold is just an active culture. Don't know anything else.
I'm guessing that if I remove the infected drywall and use some type of mold kill on the wood behind and areas around the infection that I should then be able to redrywall and never see the mold again. This assumes that the area behind is dry and not continuing to be a suitable base for mold to be active. I'm planning on let it dry out for several months to be sure it is dry after I treat the areas and before I add new drywall.

• Anyone no more specifically what I'm up against?

• What to use to kill the mold?

• If I'm analyzing the problem correctly?

Thanks for any advice.

[Bert Kemp]

Heres a great page on killing mold hope this helps.

http://blackmold.awardspace.com/kill-remove-mold.html

[Jamie Buxton]

The usual wisdom with mold is to remove the moisture source. Mold needs water to live. If it is still living, it is getting water somehow. So the fix for mold is to make sure the leaks or condensation or whatever is providing the water gets stopped.

[Mark Bolton]

Concrobium

[Sam Murdoch]

Concrobium

Had to look that one up. I'm reading that I should get a Haz Mat team in to do this work :eek:. And as I reading from the link I'm wondering
if this stuff is NOT MOLD but rather efflorescence :confused:. More to read and to test. Thanks.

[Dan Hintz]

And as I reading from the link I'm wondering if this stuff is NOT MOLD but rather efflorescence :confused:.

This was going to be my suggestion... I think you're seeing minerals, not mold.

[Art Mann]

I have never seen or even heard of white colored mold. I don't believe what you are seeing is alive. Like Dan, I believe you are on to something with the idea it is efflorescence.

[Sam Murdoch]

I have never seen or even heard of white colored mold. I don't believe what you are seeing is alive. Like Dan, I believe you are on to something with the idea it is efflorescence.

I will know for certain tomorrow but I can tell you that this stuff does spread. The "infected" areas have gotten bigger and the stuff is not just a stain but is puffy like a white moss. Anyone else sen this on drywall? Nothing special about this wall cover just your basic board from the lumber yard.

[Chris Padilla]

Post some pictures, Sam! We like pictures!

If it is mold, try some cleaning vinegar (6% as opposed to 5%) usually found at wally world. Spritz it on full strength.

[Myk Rian]

By chance, did the drywall come from China?
That crap has been blamed for all kinds of troubles.

[Larry Edgerton]

Killing mold is not possible. Like the post above said, eliminate the conditions that it needs to grow is your only answer. Mold is everywhere, its in the air we breath, and once it finds a place comfortable to raise a family it moves right in and propagates.

A good read is http://joelstiburek.com/ this guys book on houses in Northern climates. He explains how these things happen and what we need to do to build an efficient house that is also safe to live in.

Larry

[Chris Padilla]

Of course mold can be killed--its immortal? ;) You can kill off infestations of it but I agree that the conditions in which it thrives need to be removed or it shall return.

[Sam Murdoch]

Photos tomorrow. I'm going in… :eek:

[Brett Luna]

I have never seen or even heard of white colored mold. I don't believe what you are seeing is alive. Like Dan, I believe you are on to something with the idea it is efflorescence.
There are plenty of white(ish) molds around. I intentionally grow a white velvety type (Penicillium nalgiovense) on home made salami. I just don't know if white molds are common in the damp, dark recesses of our homes. I've only seen the black variety.

[Chris Padilla]

Molds come in tons of colors! (http://www.mold-killer.info/black-mold-color/)

[Pat Barry]

Kilz or Binsert. The oil base versions.

[Sam Murdoch]

As promised here are photos. I am now certain that this is efflorescence NOT MOLD.

From a web site on the subject -

"Here are a few tips that inspectors can offer their clients so that they understand the differences:
- Pinched between the fingers, efflorescence will turn into a powder, while mold will not.
- Efflorescence forms on inorganic building materials, while mold forms on organic substances. However, it is possible for mold to consume dirt on brick or cement.
- Efflorescence will dissolve in water, while mold will not.
- Efflorescence is almost always white, yellow or brown, while mold can be any color imaginable.

The second photo shows a corner in shadow but that area was white as in the 1st photo.

300624 300625 300626

I have removed all these areas (and other in the house) and as you can see in the last photo there was definitely water coming down the wall from the skylight above. The skylight is now waterproof again and the wall is dry BUT I have removed the sheetrock and plywood that you see in the photo all the way to the framing. Will let dry - treat with some anti mold (why not) and recover.

Thanks for sharing your thoughts on the subject.

[Jason Roehl]

Looks like you have both there--the first two pics look like efflorescence, and the last pic looks like mold on/in the wood. Use household chlorine bleach diluted with 3 parts water to kill that (take precautions--gloves, goggles, fresh air, etc.). Let it sit for 15-20 minutes before rinsing it off.

[Larry Edgerton]

Sam, when I build a house and they insist on skylights, a bad thing in this climate and I expect yours as well, I make the clients sign a waver that basically says: I know that the skylight will leak in the future, its not if but when."

Usually the leak can be traced back to ice forcing apart the seal/glass connection in the winter months. No matter of care during installation can cure that.

Fill that hole!

Larry

[Andrew Joiner]

Sam, when I build a house and they insist on skylights, a bad thing in this climate and I expect yours as well, I make the clients sign a waver that basically says: I know that the skylight will leak in the future, its not if but when."

Usually the leak can be traced back to ice forcing apart the seal/glass connection in the winter months. No matter of care during installation can cure that.

Fill that hole!

Larry

I'm with you Larry. Why have a hole in a roof? You can let light in with a window.

[Sam Murdoch]

Skylights may not be a wise choice but they are there and so I work in spite of them. I think they'll be OK from here on out.