How to get rid of paint on concrete floor

yummy mummyh · December 10, 2008, 08:08 PM

Hello everyone. I just found this forum and thought I would ask you experts this question.

How would I remove paint, I think its oil based from the concrete floor before I install ceramic tiles.

I don't want to use any professional sander. I want to do it by hand. Any suggestions?

Thanks

Kman · December 10, 2008, 08:47 PM

I posed the same question a few months ago and this is the reply that one of the other forum guides gave me:

The general "rule of thumb" has always been that any type of coating on concrete is a bond-breaker when it comes to installing tile.

Tile should not be installed over sealed concrete. paints and epoxies constitute a sealer.

The only acceptable methods of removal would be:
Shot-blasting,
Sandblasting,
Grinding.

No strippers, no chemical emulsifiers.

I have not found this information to be incorrect, or found any other information to add since then. Moreover, I trust Bud Cline, who provided the above answer. I bid a job for the same thing, my plan was to sand the paint off with a flooring sander. As it turned out, the customer decided not to go with the paint removal after all.

kwfloors · December 10, 2008, 09:59 PM

I just finished doing a Church that had painted floors. The guys I hired to strip it used a shot blaster and it was a great job. It takes it all off. They had to scrape the edges as the tool missed about 2 inches around the room. They also had a floor buffer with carbide cutters on it but the concrete was too soft and it would dig into the floor. This was on latex paint and it would be different on oil based paint but I know the shot blaster would do the trick. Maybe you can rent one and depending on how big the area is you could scrape it with a sharp 4" scraper but I would wear a mask. How old is it? Is it lead based?

yummy mummyh · December 11, 2008, 06:31 AM

Thanks for all your help.

My basement concrete is 70 years old, and the paint on it is only about 5 years old, and i think it is oil based. How would I know?

Also, underneath is the old paint that probably has been there for a long time, which I am certain is oil based.

I don't want to use any power machine as I think it will send me flying in the air.

Is there any tools that I can use by hand to remove it?

Thanks again.

I also trust Bud Cline. I think he knows what he is talking about......

Tandy Reeves · December 11, 2008, 07:28 AM

Folks you have the answer, it may not be the one you wanted, but if that is Bud's recommendations you can take it to the bank. Therefore, do as said, don't look for ways around it (they will fail) and do the job right.

Remember if you don't have time to do it right, when are you going to have time to re-do it?

yummy mummyh · December 11, 2008, 09:12 AM

You are right, it isn't what I want to hear but I will get rid of the paint.

I just want to know if there is any way that I can do it by hand. I don't really care about how labour intensive it will be. I have been working renovating this basement for 2 years.........what's another 2 years.........

stullis · December 11, 2008, 09:28 AM

kwfloors said

... depending on how big the area is you could scrape it with a sharp 4" scraper but I would wear a mask....

4" razor/paint scrapper can be found at most places that sell paint.

Have fun.

Personally I would check out a different product.
Additionally the use of a high quality thinset may do the trick as far as adhesion. Still the bond is only as good as the bond of the paint to the concrete and then the bond of the thinset to the paint.

Peter Kodner · December 11, 2008, 09:33 AM

A hand scraper or sander will not get the paint that is in the pores. You will need a mechanical action to do this. A small grinder would be easy to handle but you will need one that has a diamond cup wheel (for concrete grinding) and a dust shroud. You must hook the shroud up to a vacuum that is rated, at a minimum, for drywall dust. You do not want to breathe in concrete dust much less oil based paint particles. A respirator would be a good idea (fairly cheap but get a NIOSH approved paper one).

I would have a sample of the paint analyzed before I would touch it myself...

I own a Bosch 1773AK surface prep unit that has a built in shroud and port for the vacuum hose. Used right, there is virtually no torque movement, i.e. it doesn't move or twist in my hand. The 510 cup is the one you would want for concrete. Be careful using it- you can take material off very quickly with it! Maybe you can rent one as they are a bit pricey (or in Mn. talk: "spendy") to buy.

Here is a link to this tool: 5" Concrete Surfacing Grinder/ Model: 1773AK

stullis · December 11, 2008, 11:04 AM

That is a handy tool Peter.

The diamond cups are the "spendy" part.

You could buy the tool use it and then sell it. It would probably be cheaper than renting.
You will still need to hand scrap the corners.

Peter Kodner · December 11, 2008, 01:01 PM

I really like the brushes to seal the housing instead of plastic. Easy to change out and with a decent vac it does not let any dust escape. I paid about $425.00 and found it local. You are right about the cups. A replacement is about 150. You can sharpen them with talc stone.

Done several hundred square feet (all in small moisture test areas) with it in the last month and love using it.

I do wish I had upgraded my hammer drill too though. Have my eye on a nice Bosch SDS series. They have a very sweet dustless unit

Tandy Reeves · December 11, 2008, 02:36 PM

If it is work you want to rid the area of paint, get a bush hammer or bush chisel (both can be purchased at your local hardware store) and start banging away. You will have to patch the area after chipping out the concrete, but the paint will be gone.

Bud Cline · December 11, 2008, 02:45 PM

:roll eyes:

rusty baker · December 11, 2008, 03:32 PM

Have you considered a floating wood floor instead of ceramic?

Tandy Reeves · December 11, 2008, 03:59 PM

I know Bud, stupid idea, but it fill the want list: 1. Wants to do it by hand, 2. no power tool use, 3. don't care how labor intensive.

What would be better?

Bud Cline · December 11, 2008, 05:39 PM

I suspect.....

One way is to use a belt sander. The belts will load with the paint and be rendered useless almost immediately. After a few minutes the paint will get hot and smear still sticking to the substrate. Dust will be minimal however.

Another way is to use a sanding disc on a drill motor. The discs will load with paint and be rendered useless almost immediately. After a few minutes the paint will get hot and smear still sticking to the substrate. Dust will be an issue.

Another way is to use a right angle grinder with an abrasive wheel or cup. The abrasives will load with paint and be rendered useless almost immediately. After a few minutes the paint will get hot and smear still sticking to the substrate. Dust and flying particles will be a serious issue.

A diamond cup would work. Progress would be minimal but in time it could be done. The issue there is the cost of the tool and the cost of the cup. The diamond cup will not load with hot paint but the heat will build rapidly and you run the risk of ruining an expensive cup. If segments begin to fly as they dislodge from the heat this could be a very serious injury issue.

A larger hand-held floor planer with a diamond cup and dust collection shroud would also work. This would make good progress and would cause minimal damage to the substrate. A cup with a double row of diamond segments will run cooler than one with a single row of segments but heat build up and resulting damage could still be an issue. Even the air drawn by the vacuum doesn't cool the cup sufficiently. I have a 7" Fein, the whole rig only cost me about $800. Oh, then there is the cost of the vac, another eighty bucks. The vac filters must be cleaned after about every 8-10 minutes of run time.

Keeping in mind of course that cement dust is dangerous and hazardous to your health. The paint is old enough to contain lead. The proper face gear is not the 89 cent face mask at the hardware store. A face mask with NIOSH or MSA approval should be used and the mask should be the type with interchangeable cartridges.

A scraper of any description is a waste of time, it just won't work, period.

You also have to keep in mind that to do this properly so that adhesion is in your future, previously sealed pores in the concrete must be re-opened. This is impossible. So the thing to do is to expose new pores that are now below the surface. This can't be done with a wish and a prayer and some misguided determination.

Now before someone decides I am a pampas ass I can tell you that I have personally performed all of the above procedures over the years and I am convinced I have experience at this. Trust me!

Of course I am a pampas ass but a pampas ass that knows what he is talking about on this subject.

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