mold on concrete wall

[JHZR2]

Hello,

Our home is in an area with a high water table - lots of folks have water in their basements. We dont, but we have had issues with gutters and water getting in because of that.

The previous owner put a concrete fascia over the concrete basement walls (the kind where one nails a metal mesh and then puts concrete over it). Over that is waterproof paint.

We have seen some efflurescence on the walls, but recently have seen a purple mold. Must be because of moist wet conditions behind the paint. It has come through, and Id like to clean it. My thoughts:

-spray heavily with vinegar
-wash down with sponges
-scrape away what is there, not too hard as to destroy the concrete too much
-vacuum with HEPA vacuum
-re-paint with waterproof paint

How does that sound? Ive fixed all issues with gutters and water flows from the house. Should be much better. I have a few spots around the basement where I am seeing this, but one spot in particular is of concern, as we are getting a new exercise bicycle next week, and I want to be sure that we have it taken care of by then.

Thoughts??

Thanks!

 

[danster]

There are products in the paint department of your nearest Home Depot, Menards or Lowes.

They are not expensive and work well to neutralize the mold. It will likely take repeated sprayings (spray until saturated, let dry, repeat) but usually makes the mold dissapear if you are patient. If not patient some scrubbing isn't bad. The surface this stuf leaves is then mold resistant.

To fix this though, you probably need to fix the drainage around your foundation.

 

[JHZR2]

Thanks, I'll keep going with vinegar as it is more natural of a means, and then will see about coating before painting...

 

[Boomer]

Clorox is probably much more effective than vinegar. Alsdo, run a dehumidifier in the basement to keep moisture under control.

 

[duaneb9729]

They use a mixture of 50/50 bleach and water around here, sprayed on and scrubbed with a stiff brush.

 

[demarpaint]

Clorox is very good at killing mold. You are better off applying it straight, as some mold is actually pretty tough. Make sure the basement is dry, because if the mold is growing behind the wire lath that the "concrete facia" was applied to it will bleed through somewhere else. Give the bleech time to work, and re-apply to be certain you've killed all of it. If you plan on painting it use an exterior latex house paint, or a waterproof basement paint, they are fairly resistant to mold. DO NOT USE AN AKLYD OR OIL BASE PAINT!!!!!!!!!!!!! They also make an additive you can pour into the paint to give it some additional mildew resistance, that is unless the EPA banned it recently.

 

[Solo2driver]

Bleach + water in a spray bottle....be sure to have proper ventilation, should not breath that stuff in either.

 

[Oldmoparguy1]

Originally Posted By: duaneb9729
They use a mixture of 50/50 bleach and water around here, sprayed on and scrubbed with a stiff brush.


+1

I've done that many times. Most times don't even need to scrub..

 

[cornfused]

Definately the watered down bleach, But I'd be worried about remaining mold behind this fascia that you cannot get to???

 

[mrsilv04]

Enzyme cleaners. Better than any bleach on mold.

 

[JHZR2]

me too... but unless I rip it all off, I won't know.

I figure if it is all painted, sealed, and closed, the spores can not get out (they arent that mobile), and it should be contained.

What is the difference between mold and mildew? This stuff is a purple discoloration, and then there is efflorescence. No spores of any sort.

 

[JHZR2]

Originally Posted By: mrsilv04
Enzyme cleaners. Better than any bleach on mold.



Where does one get the so-called enzyme cleaners? What brand/type would I be looking for.

 

[JackFish]

OK, my landlord has a phd in chemistry and works in a lab.
Had some mold on the carpet in the basement and he came by today with some hydrogen peroxide and cleaned it up.
The stuff he brought was a 40%, not the 3% stuff you get at the pharmacy. They use it in hospitals for cleaning wounds I think.
Industrial strength.

 

[L_Sludger]

Just keep the bleach away from the ammonia!

 

[Virtuoso]

+1 on the diluted bleach, watertite paint sealer, and foundation drainage fixes.

 

[benjamming]

40% H2O2 is pretty dangerous but JHZR2 knows about that I'm sure. For example, > 10ppm requires SCBA. Not that bleach is harmless (1 ppm exposure limits as well due to chlorine), but I would go with the bleach (sodium hypochlorite) first especially for a large area.

Why dilute consumer grade bleach? Is it not already ~ 5% sodium hypochlorite?

 

[demarpaint]

Originally Posted By: benjamming


Why dilute consumer grade bleach? Is it not already ~ 5% sodium hypochlorite?


+1 we use it straight all the time. Wear gloves, eye protection, and an OSHA approved mask if you're worried. Open up a window. If you cut consumer bleech by 50% you might not kill the mildew.

 

[CROWNVIC4LIFE]

Originally Posted By: duaneb9729
They use a mixture of 50/50 bleach and water around here, sprayed on and scrubbed with a stiff brush.


Mold is a huge issue here when people go away in the summer and are too cheap to leave the a/c on in jungle humidity...The 50/50 mixture works well on the walls here...Even though they are not basement walls it works well for the people who get the mold.

 

[Loobed]

The best thing I found for killing mold is hot water and clorox bleach in a hand pump sprayer. Spray it on, scrub with a brush if needed, spray again to rinse. pat dry with paper or cloth towel and let dry. If you are going to paint I suggest and undercoat of KILZ. That stuff will cover ANYTHING and keep it from seeping through the paint. Expensive but worth the price. If you get cheap and buy another primer, you will end up buying this stuff anyways.

http://www.kilz.com/

 

[JHZR2]

Interesting on the kilz. Perhaps Ill paint with the hydraulic paint (or whatever it is called), and then coat it with kilz. This way the waterproofing does its job first and foremost...