OT: Mold? on Ceiling in House

[Paul Alciatore]

Off topic, I know, but there are a lot of smarts here so here goes. Our den ceiling is a cathedral style and it has a dark spot that has been developing at the peak for some years. We are in Beaumont, Texas so humidity is fairly high here and I don't think it is a roof leak. My wife believes this is "toxic mold" as this is a term she has heard. I don't know. The ceiling design probably prevents any attic inspection as there is only a foot or two of space between the ceiling and the roof there.

My question is, how can I determine what this is and what can be done about it. I tried spraying it with a bleach solution a few years ago, but that did not stop it.

[rancherbill]

A couple of thoughts, first you imply that at one time this did not exist. My thoughts are you have a roof leak or your roof vents / soffit is partially or completely plugged and not giving you ventilation. The moisture has found a way to get to this particular area.

There are paints that are made for this. They dry extremely quickly to seal the area before the mold seeps through the paint.

[Tinkerer]

Most likely it's under the paint... so washing it will do nothing. Cut the black spot out and repair that section. That will allow you to have a peak behind it and calm the wife... also not all mold is toxic.

[cuslog]

Log Home builder here, so I have dealt with a few cathedral ceilings.

The first thing I would suspect is a condensation problem and the moisture is probably making things damp and dis-colouring the materials.
Lots of cathedral ceilings have been built in the past either without a vapour barrier or a poor job of the installation of it. That fact, combined with inadequate roof ventilation will cause condensation in the colder months.
If this is in fact the problem, about your only option at this point is to upgrade (increase) your roof ventilation or reduce the moisture level in the house with upgraded bathroom and kitchen fans.

Hope this helps.

[Cheeseking]

Log Home builder here, so I have dealt with a few cathedral ceilings.

The first thing I would suspect is a condensation problem and the moisture is probably making things damp and dis-colouring the materials.
Lots of cathedral ceilings have been built in the past either without a vapour barrier or a poor job of the installation of it. That fact, combined with inadequate roof ventilation will cause condensation in the colder months.
If this is in fact the problem, about your only option at this point is to upgrade (increase) your roof ventilation or reduce the moisture level in the house with upgraded bathroom and kitchen fans.

Hope this helps.

I agree with this assessment. Although whenever I hear "vapor barrier" my head wants to explode!! They cause more harm than anything in wall assemblies.

[dp]

Some inspectors have boom mounted digital cameras to get to the really tough spots. Any mold should be considered toxic until it is known it isn't. If your canary is face down on the pan of its cage you should probably collect some laundry, go to a laundry mat, then rent a room. Not be be hysterical, but some of those fungi are as happy living in or on you as they are your walls.

If nothing else a spritzer of ammonia aimed at the worst of it would be a good idea before hitting the pillow.

[garagemark]

The best and easiest way to find the issue is with a GOOD thermographic image of the area. It will show if a piece of insulation has shifted, or if you do indeed have water intrusion. A couple of shots of the ceiling will give you a good indicator of what is wrong.

Since mold thrives in moist or humid environments, it is logical that you have a damp (albeit probably slight at this time) spot.
We covered this type of issue extensively in the FLIR level one training I attended last year in Miami (it was five of the most interesting days I have spent for my work. They finally sent me to something worthwhile ).

If you don't have access to a good camera, there are companies that can do it for you for a nominal fee. But if you have someone do it, it is also worth finding MANY other losses in your home. I shot my entire house inside and out for a graded project when I got back home and, oh lordy, did I get a wakeup call!
Mark

[Paul Alciatore]

Some inspectors have boom mounted digital cameras to get to the really tough spots. Any mold should be considered toxic until it is known it isn't. If your canary is face down on the pan of its cage you should probably collect some laundry, go to a laundry mat, then rent a room. Not be be hysterical, but some of those fungi are as happy living in or on you as they are your walls.

If nothing else a spritzer of ammonia aimed at the worst of it would be a good idea before hitting the pillow.

Not quite sure I would want to use ammonia as my wife is quite sensitive to odors and it is among the worst. What is the comparison between ammonia and the bleach that I tried. I was wondering if an application of stronger bleach might help it. I used about a 1:10 dilution the first time, perhaps 1:5 or even stronger? I know that an application of bleach to the ceiling above my shower helped a mold problem there. It has been gone for at least 15 years now with perhaps only one additional spraying a few years after the first.

[Black_Moons]

Spray it with a 10% solution of bleach and water, then wipe it all off after a few minutes so, While its still wet (And use a mask!, clean with paper towels, and throw those out -_-)
I doubt you want to go any stronger.. even 10% is very strong, and stronger may start to bleach things. (As in turn them white)

Spray it again after a few days. You want to basicly dampen the area without causing drips

I wonder if adding soap as a surficant would help or harm?


If smells are a problem, Peroxide is also a good steralisation agent but has no smell (afaik?), and decomposes into oxygen and water. Strong peroxide solutions will also tend to bleach things (Over 15% I believe will bleach skin as well.. and kinda burns, less is used on hair..) So try not to get it on anything... Im not sure the percent needed to have a decent effect on mold, but I suspect it would not be much, Even 10% would likey have a great effect. 3% iirc is used to treat wounds.

A quick google shows peroxide used to kill mold and them recommending 3%.

Hydrogen peroxide as I understand it basicly rips cells apart as it oxidises.. I also think the pure oxygen it releases is not that friendly to a lot of cells. Hydrogen peroxide also decays rapidly when impure.

The reason it won't kill you, is you are already coated in dead cells, And low consentrations have low penetration, Still, Would'nt wanna drink it or get it in your eyes, or inhail too much of the mist, But it should'nt matter on your skin (As they use it to bleach hair!)

[Duffy]

If it is truly BLACK, then chances are it is aspergillus niger, which as far as I know, is NOT particularly "toxic," but it sure is UGLY! Washing with dilute bleach will elliminate the colony, but it does not do the paintwork much good-it is a trade-off.
Here is the dope on concentration. Javex and similar popular brands are usually 5.25 % sodium hypochlorite, (THAT is the active agent.) For the purposes of this discussion this translates into 52,500 parts per million, (ppm,)of sodium hypochlorite in water. Water treatment plants add in the region of 5 to 10 ppm to disinfect your drinking water. Swimming pools try to use about the same amount. Cotton mills, on the other hand, use about 200 ppm in hot water, to bleach cotton snow white. Even at that concentration, there is a trade-off between bleaching effectiveness and fabric degradation.
For comparison, a 10 % solution of bleach in water gives a concentration of 5250 ppm of sodium hypochlorite. THAT is pretty strong. Personally, I would use 5% or 2625 ppm. A bit of detergent would also help wet the surface.
Hydrogen peroxide is also effective and it has the bonus of no smell. The down side is that it is hard to find. I can buy it here where I live in 30% solution and that should REALLY be handled carefully. If you were to use it, certainly in no greater concentration than bleach, but it should also be in an alkaline solution, up around Ph 8-10.
Now, the REAL problem with peroxide is that it involves TWO chemicals and that amounts to CHEMISTRY!!! This is OBVIOUSLY TOO MUCH for HSMers and will cause ALL SORTS of problems!