Mold on garage sheetrock

[infinite97]

I was up at my brothers place yesterday near Olympia WA. He asked me to take a look at his garage - they have had a recent issue with mold on the ceiling sheetrock and also on the metal garage door. I pushed and tapped on all of the Sheetrock and all of it sounds solid, nothing soft or mushy. He said they had an electrician up in the attic last week for an unrelated project and he said he saw no evidence of leaks or excessive moisture.

He has been running a dehumidifier for the last couple of days, but it’s a garage, so…

Y’all have any thoughts?

 

[freebirdwelds]

is there a moisture barrier under the concrete? if not, I'd put a sealer on it.

 

[Shiftless]

Might be moisture coming up from the concrete floor. Toxic mold is no joke.

Has he lived there long? Is this a problem that just popped up recently?

 

[P0234]

Garages are awesome places for mold to grow. Its unconditioned space, people bring in hot, wet cars, and OP is in the wet part of the world. My garage was a horror show when I bought our house.

Before anyone wets themselves on "toxic mold", please realize the stuff is EVERYWHERE. People eat the stuff (blue cheese) on purpose (yuck!) and its used to make medicine that keeps us alive, so there is zero reason to panic about it. A whole industry sprung up after most of the asbestos boogey man was nearly extinct. The only time to really get on a fast action plan is if someone is getting sick from it, which is very rare.

So with that out out the way, all you need to do is wash it off, bleach will kill it no problem but using something like concrobium will help keep it way BUT you have to keep the humidity down. 60% or less is what the EPA says. Also paint the drywall after cleaning it, a mold resistant paint will help too.

 

[Zeke]

"Bleach" is too broad a word. That having been said, there are a lot of mold remedies that use a base type solution starting with sodium this and sodium that. The mildest is hydrogen peroxide (depending on concentration, of course).

 

[P0234]

"Bleach" is too broad a word. That having been said, there are a lot of mold remedies that use a base type solution starting with sodium this and sodium that. The mildest is hydrogen peroxide (depending on concentration, of course).

Bleach is the chemical in your laundry closet, otherwise labeled as Clorox, unless you are from another country or trying your hardest to be obtuse.

 

[Steve_P]

I have this issue also. I spray it down with diluted laundry bleach, let it sit for a while, wipe it off with a damp towel, and that takes care of it for a few years. Yes, that doesn't fix the problem, but I'm not going to tear out the walls and install insulation for a minor issue. Yes, not ideal, but this isn't the black mold death **** that grows inches thick.

 

[infinite97]

Garages are awesome places for mold to grow. Its unconditioned space, people bring in hot, wet cars, and OP is in the wet part of the world. My garage was a horror show when I bought our house.

Before anyone wets themselves on "toxic mold", please realize the stuff is EVERYWHERE. People eat the stuff (blue cheese) on purpose (yuck!) and its used to make medicine that keeps us alive, so there is zero reason to panic about it. A whole industry sprung up after most of the asbestos boogey man was nearly extinct. The only time to really get on a fast action plan is if someone is getting sick from it, which is very rare.

So with that out out the way, all you need to do is wash it off, bleach will kill it no problem but using something like concrobium will help keep it way BUT you have to keep the humidity down. 60% or less is what the EPA says. Also paint the drywall after cleaning it, a mold resistant paint will help too.

He has been spot applying this product. I will let him know regarding the paint.

They use the space as a home gym; no vehicles.

 

[infinite97]

is there a moisture barrier under the concrete? if not, I'd put a sealer on it.

Neither of us know. I’ll look in to the sealer.

 

[infinite97]

Might be moisture coming up from the concrete floor. Toxic mold is no joke.

Has he lived there long? Is this a problem that just popped up recently?

6 years. Mid-2000s home iirc. He says yes, it just started happening in December for the first time. No changes that he has made or is aware of aside from replacing a fridge in the garage.

 

[cgrutt]

Provided you rule out a water leak I'd spray the entire sheetrock with a gallon of Concrobium and a garden sprayer, let it dry completely and prime sheetrock with a mold control primer and top coat with your choice of latex paint. Keep some fans running to circulate air and dry things out if moisture persists.

 

[Junkdrawer Dog]

Clean with bleach water solution and paint with KILZ mold and mildew specific primer. I had to do this in my old, damp garage back in the midwest.

 

[JoeMcGov]

How do you conclusively know it is mold and not mildew?

 

[P0234]

He has been spot applying this product. I will let him know regarding the paint.

They use the space as a home gym; no vehicles.

What’s the humidity level in there? A cheap digital gauge with min and max will be useful.

As for the concrete being the source of moisture, tape a clear sheet over a 3x3 area and see if you get condensation under it.

 

[PCustoms]

That 1st pic looks like a crack running along the fuzzy mold clusters.....

I bet there is (or was) a leak on top of the ceiling, someone needs to get up there and thoroughly check in that area

 

[lzenglish]

Kill It, Scrape It, Paint It, and Tell as Few People as Possible about it. I had it in the shower stall, and adjoining room when i first moved in. I Just cut it out of the (sheetrock), and replaced same.

LZ

 

[infinite97]

What’s the humidity level in there? A cheap digital gauge with min and max will be useful.

As for the concrete being the source of moisture, tape a clear sheet over a 3x3 area and see if you get condensation under it.

He said he bought a gauge online and will start checking it tomorrow.

Thanks for the idea on the plastic!

 

[infinite97]

That 1st pic looks like a crack running along the fuzzy mold clusters.....

I bet there is (or was) a leak on top of the ceiling, someone needs to get up there and thoroughly check in that area

Yes, quite a bit of his ceiling drywall tape is cracked. I asked him about it yesterday, he said it’s been like that the whole time they’ve lived there. In one area near the pull down stairs, the previous owner missed a beam and fell through the drywall

As I mentioned, I performed the foolproof push / knock test on the drywall and didn’t sense any water issues. My brother said he’ll climb up there soon and check it out.

 

[Zeke]

Bleach is the chemical in your laundry closet, otherwise labeled as Clorox, unless you are from another country or trying your hardest to be obtuse.

What i was inferring is that you can use pool chlorine which is the same chemical as grocery store bought compound in a stronger solution. For years I have bought pool chlorine and diluted it to 25% of the pool contents with water. That makes it approximately 'bleach'.

I could use 1/4th of the amount of store bleach but it can hurt clothes if not mixed quickly by the washer and it confuses my wife. Better to just refill the store bleach bottle with 25% chlorine (which technically not what you're buying as chlorine is a gas) and 75% water.

This is common practice amongst roof cleaning companies that are limited to the amount of chemical they can carry on a truck by the DOT. Once at the job they do the dilution. Another thing is that the stronger solution costs about the same as the grocery store "bleach." So they get a lot more for their money. AFAIK this is perfectly legal.

 

[zendriver]

Y’all have any thoughts?

Mold forms in moisture.

Where's it coming from?

 

[Sturgeon]

What ever decisions are made don't get ProServe involved, they'll be checking the neighbors for mold as well.

 

[lzenglish]

What ever decisions are made don't get ProServe involved, they'll be checking the neighbors for mold as well.

Well Said ! Might just as well tell the world you have the "Bubonic Plague, As Your Wallet and Bank account "Could Be Tapped Heavily". I witnessed this on a Commercial Scale first-hand, the last few years I Worked before Retirement. "NEED TO KNOW BASIS ONLY" ! FIX IT Yourself, but Be Sure You Fix It "Sooner Rather Than Later"!

LZ

 

[johnre]

Is the garage attached or separate?

Is there any forced air circulation?

An inexpensive preventative once it's cleaned up is one of these; I've got this model for my small enclosed shop area. It pulls about a half liter per week out of the air. I'm in the same climate zone as your brother:

https://www.amazon.com/Dehumidifiers-TABYIK-Dehumidifier-Bedroom-Bathroom/dp/B09TSZTMZ2/?tag=atomicindus08-20