# Another Concrete Floor Question



## BhamPainter (Mar 6, 2013)

Hi all . . .

I'm painting a residential concrete floor in a basement. I want a durable floor finish that's not going to break the bank or have me forgetting my name after applying it in a confined space. The floor will see foot traffic, but no cars, and it looks to me as if it has never before been coated. I've seen a variety of opinions about floor coatings in these situations, so I would just like to have a few people check my process/materials.

Here's what I'm thinking:

There are some uneven surfaces, including 50+ year-old tile adhesive, that I plan to grind off with an angle grinder or chip off with a flat bar. The floor doesn't need to be super-smooth, so then I'm planning to sand with a stone-approved pad on the angle grinder, then finish with sandpaper on a random orbital if necessary.

Next I'm going to do an all-over etch/clean with phosphoric acid, since the floor is old and dirty.

Finally, I plan to coat with 2-3 coats of Benjamin Moore latex floor-and-patio enamel. I'll thin the first coat, as per manufacturer's directions, to help it penetrate, and give it the allotted overnight dry.

Anything I'm missing here? Any thoughts on this product? I've used it in basements before with no complaints, but some people seem to think I need a sealer underneath. It's only about 500 sqft of surface, so I don't mind going for a higher-end product if people think it really won't hold up.


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## Epoxy Pro (Oct 7, 2012)

We are currently painting a basement on a 6,500 sqft home, the floor was very smooth, dirty and some staining, we rented a scarifyer to scuff up the floor. We also used the porch and floor BM paint, this is our 4th one with this product and so far it is holding up nicely. We did scarify all the other floors as well. The problem with acids is the can be blotchy and inconsistant this is why we rent the machine.


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## NACE (May 16, 2008)

StepUpBham said:


> Hi all . . .
> 
> I'm painting a residential concrete floor in a basement. I want a durable floor finish that's not going to break the bank or have me forgetting my name after applying it in a confined space. The floor will see foot traffic, but no cars, and it looks to me as if it has never before been coated. I've seen a variety of opinions about floor coatings in these situations, so I would just like to have a few people check my process/materials.
> 
> ...


Did you mean Muriatic Acid? Be careful with that. Attacks electrical and metal, has brutal vapors and only provides a mediocre etch. You should also neutralize it after applied with degreaser. I would degrease first, the grind with no acid. That will allow you to remember your name, acid will not let you do that.


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## kdpaint (Aug 14, 2010)

I recommend what NACE and CD say. Etching seems easy, but it is a pain, and the results are not great. Grinding with a dedicated diamond grinder with dust extraction is the way to go.


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## BhamPainter (Mar 6, 2013)

So, if I grind it with an angle-grinder, is that as good as scarifying? The concrete grinder I saw at my local rental shop seemed like it would really tear the floor up, so I didn't want to use it. If I scuff, does that negate the need to etch? I'm just worried about any other oils and residues that may still be on the surface after scuffing.

And to etch, I did mean phosphoric acid. I've heard that it is not quite as effective an etcher as muriatic acid, but that it has lower fumes, and still gets the job done pretty well. Any experience in this regard?


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## BhamPainter (Mar 6, 2013)

NACE said:


> Did you mean Muriatic Acid? Be careful with that. Attacks electrical and metal, has brutal vapors and only provides a mediocre etch. You should also neutralize it after applied with degreaser. I would degrease first, the grind with no acid. That will allow you to remember your name, acid will not let you do that.


What would you recommend as a degreaser?


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## Epoxy Pro (Oct 7, 2012)

StepUpBham said:


> What would you recommend as a degreaser?


There is a new degreaser out, i can't remember the name of it, check with your local Bem Moore store as it is their product. I heard the way it works is it is real good, forms like a soapy suds and attacks the grease and will not damage the floor or ruin the finish.
As for the angle grinder it will work but it will take a long time, I use a small scarifyer (single head) for basements and can get thru one in a couple hours, hand grinding could take a day or more. It comes down to how you priced it and what will work best on your job. I rent the small one for $195.99 a day, the larger 3 head one for $250 a day. We have also been very lucky and the 6 basements we have done so far were for new home owners so the basements were nice and empty.


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## kdpaint (Aug 14, 2010)

If it's a small basement, that $195 grinder rental CD mentioned (especially if you get dust extraction)is very worth it. I don't think a hand grinder would leave a nice even surface. The other benefit is that topcoats last longer when floors prepped are with a grinder. 

Acid needs to be washed off neutralized and washed 100%. That is a huge pain and many steps that take time. Degrease, grind, topcoat, done.


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## Jmayspaint (Mar 26, 2013)

StepUpBham said:


> So, if I grind it with an angle-grinder, is that as good as scarifying? The concrete grinder I saw at my local rental shop seemed like it would really tear the floor up, so I didn't want to use it. If I scuff, does that negate the need to etch? ?


 The angle grinder won't do the same thing as a diamond but floor grinder. I tried to use an angle grinder with various discs to do the edging on a big floor. It's hard to explain why it didn't really work. It put a texture on the floor, but within that texture the concrete was still smooth. I know, doesn't make sense, you just have to try it. 

I ended up using a diamond tip cutting bit and lightly dragging it over the surface. VERY lightly. That got closer to the sandpaper texture I was going for. 

Rent a floor grinder. Skip the hassle.


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## kdpaint (Aug 14, 2010)

Yup. Diamond grind it. You will be so much happier. I learned my lesson trying out etching...never again. Unless I want to inflict pain and suffering on myself and have my job fail.....


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## BhamPainter (Mar 6, 2013)

Thanks for the help, guys!


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## kdpaint (Aug 14, 2010)

The angle grinder will be useful for the edges that can't be hit with a diamond grinder. If you do go with etch due to $ (some jobs just don't have the budget, and an extra 3,4,5 hundred bucks on rentals can be painful, I know), just make it super clean and rinsed.


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## painter213 (Nov 5, 2008)

Rent you a small shot blaster. You can get them that runs off 110 volt and has about a 6" cut path. Will give you a much better surface for coating. Scarifying damages the concrete and makes it week. I was on a job and the contractor was going to scarify the floor and I had the to shot blast a section as well. Glued bond test dollies on both areas. Area that was scarified pulled at 175psi, the area that was shot blasted pulled at 400 psi. Needless to say the entire job was shot blasted. Also, you had better do some moisture testing on that floor. I would do at least two to three calcium chloride moisture test. You need no more than 3 pounds per 1,000 sq ft per 24 hours in moisture vapor emission. Anymore and your paint will be blown off the surface. This test takes 60 hour minimum and no more than 72. And follow the directions to a T!


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