Help with BLACK MOLD

[old bear]

We’ve had record rains the last 5 -6 weeks. Until today we have not experienced any real problems do to the rain. This morning I noticed black mold growing on the wallpaper behind the toilet located in the basement utility room.

Using paper towels I dried the wall, the toilet, and the tile floor. Then using old bath towels I applied straight Clorox bleach to the entire area, and scrubbed away the mold. I sealed all the cleanup materials in plastic bags and will dispose of them properly.

The sheetrock DOES NOT feel soft or spongy so I’m going to assume none of it will need to be replaced.

I’ve been planning on painting over the wallpaper for a year or so, (no need to rush into a project, is there?) I dried the room using a large fan and dehumidifier, then started to apply the first of what will be two coats of OIL based Kill-Z. Before I apply the second coat of Kills have I missed any steps??

Thanks all

[Rule3]

Yes, you missed the part of why your basement walls are getting wet or damp. No matter what you do inside the house to the interior walls the mold will continue until you solve the outside problem.

I do not know the construction of you basement/utility room so hard to say.

If it is concrete block foundation, then water is seeping through and until you fix that there is going to be problems. If the there is dry wall inside then it needs to be replaced. Once it gets wet it's done for.

[Gray Rider]

You wrote that the mold was growing behind the toilet; Is this the area directly behind the tank or is it the entire wall the tank backed up to? If it's directly behind the tank it could be due to your humid Carolina summers causing condensation to be continually on the tank and the wall behind it picking up that moisture and never having a chance to dry out. One cure is to get a mixing valve that sends hot water into the tank keeping it warm enough that condensation does not occur. The other is to rip out the old sheetrock and put in moisture/mold resistant sheetrock.

If the moisture is infiltrating through your block wall then that's another problem.

[JcMack]

There was a thread on this a couple years ago on this forum started by Joni I think. One thing I recall is not to use bleach because it disperses the spores. The effective alternative was peroxide.

[S&W45Colt]

Rule 3 is right. You have removed the current mold, but anytime you get moisture there again mold will return. As for how the sheet rock feels, that means nothing to a point. Your hand is almost 30% moisture, which is quite a bit. So unless it's soaked, you can't tell it. I'd recommend putting a fan down there blowing on it for 3-4 days, get yourself a cheap moisture meter and see if it's still wet after that. If it's still wet, you know you have an issue beyond the freak levels of rain we've had lately. Check it the next few months with the meter when it rains if it shows dry after using the fan.

Here's a cheap moisture meter I found.......

Amazon.com: General Tools & Instruments MMD4E Digital Moisture Meter: Home Improvement@@AMEPARAM@@http://ecx.images-amazon.com/images/I/41bOFkksKAL.@@AMEPARAM@@41bOFkksKAL

That's my 2 cents.

[old bear]

Is this the area directly behind the tank or is it the entire wall the tank backed up to?

It's the area directly behind the tank, and from floor level to 12 - 18 inches up the wall, so I'm hoping your thought of a condensation continually building up is correct.

I did not know about peroxide Vs. Clorox. I will pick-up several bottles and re-clean before I apply second coat of Kills.

S&W45Colt, thanks. I've got a H.D. fan working down there now and I will wait several days before I do anything else.

THANKS ALL

[Delos]

External (of walls) I think small flies can carry it on their feet.

Check under lip of toilet with a mirror.

Definitely look inside toilet holding tank.

Baking soda is good. Toilet cleaner is better when appropriate.

Any wetness around sink faucets can be covered with baking soda and ignored for long periods. Remove hollow bottom handles and covers (over faucet shaft packing areas), and look up inside.

A very old church nearby had extensive black mold inside basement walls. They decided to tear it down. Sometimes one needs to do some form of wall exploration. Those round saws used to cut holes in doors to mount deadbolt locks might work? (Stick plastic flowers over holes?)

(This is a non-professional opinion)

[diamonback68]

I had a similar mold problem in both corners of the cubbyhole where the toilet sits in out master bath. It turned out the wax seal on the toilet was leaking and water was seeping/oozing under the floor tile to the back wall and wicking up the walls in the corners. Plumbers replaced the seal, I replaced the drywall in that area and repainted, problem gone.

[A10]

I'd strip the wallpaper off there, wash it with a 10% bleachwater solution, and let it air dry. Wallpaper paste is like a buffet for mold....

[radar1972]

Another + to Rule3's advice: you need to find out why it got wet & moldy in the first place.

Also, is the basement utility room under your central air/heat? If not, then you need a good dehumidifier.

But first and foremost, you need to find out HOW it got moldy and fix that.

[old bear]

I've found the source of the water leak. It's the water line that fits into the toilet. I've turned the water off and will have a plumber replace the toilet and see that the water line in properly attached. As suggested I've ordered a moisture meter and will not do any further prep for painting until I determine whither the drywall needs to be replaced or not. I did pick up a quart of peroxide and will wash every down with it in the morning. For now I'm just going to watch the Braves game and let the fan work its' magic.

Thanks all,

[radar1972]

Glad you found the leak and that it is not on the backside of the wallboard.

Also glad you were able to see the Braves finally have a good day.

[eveled]

Basements should not be finished IMHO. Most places dig a hole in the ground they call it a well or a sump. Moisture problems are inevitable. If I were going to finish a basement I would not use drywall, but cement board they use in bathrooms. Definately get a dehumidifier. I also have heard that not all black mold is dangerous, and not all dangerous mold is black. Ed

[arjay]

Poke at the drywall with a screwdriver.If its soft it will need replacing.Once the moisture gets through the paper(if it did),the gypsum turns into a crumbly mess and there's no fixing it.

[sheepdawg]

I've always used Clorox on mold, always works. As to what to paint that area with, Zinnser makes a product called Perma White which they guarantee not to mildew. They actually ground the mildewcide into the pigment of the paint. Works pretty good in my bathrooms which are a Mecca for mildew. Avoid oil based anything as it compares to roast beef at the Ritz for mildew.

[scooter123]

Condensation only forms on a toilet tank when the water is colder than the Dew Point. Since an unused toilet tank is typically at Room Temperature most condensation issues with a toilet are due to a leaking valve and a constant flow of fresh water into the tank. I would suggest that you replace the gasket for the flapper valve in your tank or even replace the entire valve assembly because the high pressure valve can also develop a slow seep. As for testing for either, anytime you see condensation on a toilet that doesn't see a lot of use it's a sure bet that either the tank or high pressure valve is seeping and allowing a constant flow of cold water.

[Rule3]

Bleach or even better pool chlorine (stronger) Sodium hypochlorite is the best mold killer. Peroxide has bleaching action but not as good.

If the drywall got wet, it needs replacement, it will not dry out.

I re did both our bathrooms that water got through the tile. When the house was built they only used green board (water resistant.) What a night mare!!.

Now they use fiberglass wall board or at least concrete backer board.

Plus we live in the land of Chinese drywall (we did not have it) but look that up for horror stories!

[JcMack]

Originally Posted by sheepdawg

I've always used Clorox on mold, always works.

If this is true I owe you for a quart of peroxide.

[old bear]

[QUOTE]If this is true I owe you for a quart of peroxide. [/QUOTE

Better safe than sorry. If you are going to kill something may as well kill it twice, right?

I'm sure the Lovely and Charming will find a use for any excess peroxide. For God's sake don't tel her I said that.

[sheepdawg]

I'm in the paint business. (now I've lost all respect) Jomax is the best selling mildew remover I know of and it says you must add Clorox for it to work. Most of the commercial mildew removers use bleach, peroxide or oxalic acid for mildew but to me bleach is the best. You can remove mildew with a 3500 psi. pressure washer too but I don't think this would be the proper application for that method.