Cleaning concrete

[WhiteLightning]

Hey all. Just joined this forum since I just bought my first house. I have a question about cleaning the floor.

I have a 1.5 bay garage. The full bay goes the depth of the house. The half bay is full width, half depth. In that area they put 12" x 12" carpet tiles on the floor. Needless to say, they were filthy/damp/etc. When I pulled them up to throw them out, the carpet tiles left "square" marks, and underneath each tile was signs of mold/mildew.

My question is, what is the best way to clean this floor to make it
1. Sanitary- remove mold/mildew
2. Clean looking- remove any "square" marks, if possible.

Thanks for looking!

-Andrew

 

[WhiteLightning]

40 views and not one recommendation?!?

 

[GtiKyle]

Whoa, chill... It's been less than 2 hours.

Mold and mildew can be neutralized with bleach. 409 makes a spray that will kill it all, let it soak. Don't agitate it until it's been fully soaked and killed. Even still, it's good practice to wear an appropriate respirator.

As far as cleaning the marks, i love using Simple Green, and a good stiff bristle brush. A long brush used for cleaning RV's will keep your back and knees happy too.

 

[WhiteLightning]

Thanks for the reply. Another friend recommended simple green as well.

I was planning on trying bleach/water mixture first. Then I'll hit it with 409 spray. Lastly, clean it with simple green.

I'll take some before/during/after photos and report back.

Thanks!

 

[GirlnAgarage]

Deck brush, a good cleaner and water hose.

 

[WhiteLightning]

Update:
Went to the house last night and to my surprise, the floor looked a little better than it did when I first removed the carpet tiles. The floor was dry and looked better than the other night.

I went to Ace Hardware to get some keys made. While I was there, I asked the salesman what he would recommend for solving this little problem. He recommended:

So I purchased that and a gallon of simple green concentrate. The plan is to hit the floor with some bleach/water solution to kill any mold. Then use this Wet & Forget followed by some simple green for a final cleaning. If the marks don't totally dissapear, I am okay with that. I just want it to get a little bit better.

After I do that this weekend I can start on my workbench project!

 

[superdel]

It has been my experience that if it says it is good for the environment (non caustic/acidic, no bleach etc.) it doesn't work. For mold and mildew use bleach or better yet, sodium hypochlorite. Be careful as it will turn colors white and kill vegetation (that's why it works for mold.) Clorox is about 6% sodium hypochlorite. If you get straight sodium hypochlorite, it is the maximum you can dissolve in water (about 16%). Works really well and is not dangerous. Ask your local pool supplies place if they have some or your local water/sewr treatment facility should have some they will let you have. An even safe bet for the mildew is tri sodium phosphate (TSP). It will not hurt any vegetation, but you have to scrub a bit. SH will work instantly, you have to use a bit of agitation with TSP. TSP is readily availabe at the big box stores or hardware store. Just don't get the "environmentally friendly" type, it will not work.

 

[WhiteLightning]

To give everyone an idea of what I'm working with. I will try cleaning it this week or during the weekend. Stay tuned!

 

[theoldwizard1]

If it is mold/mildew or algae you have to use something with chlorine (bleach) to kill it.

 

[jhutch]

Do you just want to clean it, or looking for a floor finish, after removing the residue from the carpet tiles?

 

[WhiteLightning]

I just want to rid of the mold/mildew that still exists and try and get those lines up as much as possible. I plan on leaving it bare concrete.

 

[Flooring For Garage]

Honestly... I wouldn't spend much time or money on trying to clean this up with chemicals. Either rent an industrial floor sander (or hire someone who has one). From your photo, it looks like you'd have to do tons more of what you're already doing to make any real progress. I'd grind it down and start with a reasonably "fresh" surface to finish.

 

[GirlnAgarage]

You know, the squares in the concrete look kinda cool. It got me to thinking that might not look so bad with a light shadow affect under a nice stain. Not certain if that's chemically possible. I was just thinking it adds visual texture.

Anyway, OP that is a heavier coverage than what I thought. It looks like the centers of the squares are stained/mildewed/glue(?) and the outside edges is the "good" concrete? I was thinking the opposite, that the majority of the cement was good and the edge lines were bad. That is a lot. At any rate, I would still clean it. Bleach hot water and a deck brush then a good rinse. See what that cleans. I'd guess that anything past that will involve more money and work to really get rid of and cover. You'd actually be doing the floors with an appropriate product/finish/mechanical refinish. Guess it just depends how far you want to go and spend on it.

 

[WhiteLightning]

I'm just trying to kill any mold/mildew, and then clean it some. I don't expect the "squares" to dissapear without spending some cash on machines/etc. The centers and edges are mold/mildew.

We'll see what happens.

 

[JakeKohl]

To give everyone an idea of what I'm working with. I will try cleaning it this week or during the weekend. Stay tuned!

Some people work really hard with stains to make a floor look like that. Clean it, and seal it.

 

[GirlnAgarage]

I'm just trying to kill any mold/mildew, and then clean it some. I don't expect the "squares" to dissapear without spending some cash on machines/etc. The centers and edges are mold/mildew.

We'll see what happens.

Yeah, just the bleach and hot water. I used that mixture on our deck to get rid of the mildew that was building up in the corner. It really brightened up the place. That was two summers ago. I'm starting to see a little mildew come back, but that is because the deck is outdoors and it is to be expected. Since you pulled up that carpet that was trapping moisture your floor ought to hold out better long after the cleaning, especially that the cement is no longer covered and keeping moisture. It can evaporate instead.

 

[Craftsman86]

In the flooring industry we commonly have to acid wash a floor before it can be tiled, Muratic acid is relatively inexpensive, A good respirator, gloves, and goggles along with some good ventilation and you should be rid of the stains. As it was mentioned previously in the thread the Tile lines will come back randomly on you. If you do the acid treatment you will have to reseal it afterwards.