Cleaning mold without bleach?

DavidRFebruary 13, 2014

I have a rental house where the downspouts weren't drained right. The downspouts are fixed now, but there are large areas of grey mold on the basement block in the corners from the moisture. My new tenant (understandably) wants them GONE.

Plan A was to spray down the areas with bleach, let it sit for a while, then power wash. (There are floor drains.)

The problem is that the previous tenant had cats, and they had some accidents on the basement floor. There is a mild but definite urine odor.

I'm concerned that leftover ammonia from the cat urine will react with the bleach, and the resulting chlorine gas will drive me out of the basement (or worse).

I guess I could force-ventilate the basement with fans, but it still seems risky.

Can anyone suggest a good NON-CHLORINE BLEACH cleaner that can remove the mold from the walls? Preferably one that doesn't cost an arm, leg, and the left ear.

The walls don't have to be spotless, but I'd like to get rid of most of the active mold. I plan to paint the walls once they're reasonably clean.


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You are correct that bleach and cat urine do not mix well. Try Krud Kutter Mold and Mildew Stain Remover. It doesn't contain bleach and can be used for interior and exterior projects. I purchased mine at Wally World.

    Bookmark   February 14, 2014 at 2:00PM
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I failed to mention you will find Krud Kutter in paint department.

    Bookmark   February 14, 2014 at 2:06PM
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Arjay, thanks for the tip. I'll try that next time.

After a lot of poking around the net, I found several suggestions calling for various amounts of TSP and borax. (Did you know you can make your own version of that popular $9 per quart mold control spray by mixing a gallon of water, 2 tbsp of borax, 2 tbsp of baking soda, and 1 tbsp of TSP?)

I ended up mixing about a half-cup each of Savogran TSP and Twenty Mule Team borax in 2 gallons of hot water, and scrubbing down the walls with it using a long-handled stiff brush (that stuff is downright vorpal if you get it on your skin). That and the power washer got almost all the nasty stuff off the walls.

The smelly floor is another matter. Phew! Nice kitties. (Not.) Anybody have a homebrew recipe for an equivalent of those expensive "enzyme" pet odor removers, such as Nature's Miracle?

    Bookmark   February 25, 2014 at 5:32AM
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Good information here, thanks for sharing.

A carpet installer some years ago recommened Oil of Wintergreen from the pharmacy counter. Diluted and put in a pump sprayer then saturate the concrete floor. Let sit and evaporate on its own. It worked quite nicely on dog urine stain/smell in a former home. Worth a try as the small bottle wasn't that much if memory serves.

And though not homemade but have had good luck with Odoban from Sam's/Costco. Comes in a gallon jug and you dilute as needed. I would use it full strength on the cat urine affected floor. Spray on generously and let air dry. It might be $20 or so but it makes a ton.

    Bookmark   February 26, 2014 at 6:29PM
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