I put primer on my garage floor, but...?
Question:...I got our garage floor power washed, etched, and chlorinated to prep it for painting.
It had huge oil stains. Then, I swept it, and put primer (for concrete--Behr) on the floor. The patches where the oil stains were, are still showing through the primer. Those areas were cleaned and etched so I don't understand what's going on.
I don't want to waste a lot of paint if those patches won't be covered.
Has anyone primed with Behr's concrete primer before? I didn't realize it would be thin like water. They told me I needed 2 gallons for my garage, but I got it all in one gallon. Do I need to put another coat of primer on the floor before I paint with concrete paint--Behr?
Answers:
prime it again and maybe a 3rd coat. I assume its a water based sealer and this happens when water based primers are used with tough stains, even on cedar and other wood with lots of tannins in them require 2 to 3 coats of primer/sealer to seal. The behr concrete stain is about the only good product I use, painted many concrete floors and pool patio's with good results. Stains are thinner and on any paint or staining job 2 thin coats are better than one heavy coat. My personal opinion you should have used the Rustoleum garage epoxy floor kit with that said the answer about thickness of paint film is bogus. Good luck Les the painter, I meant spot prime your areas not the whole floor! DO NOT SEAL THAT FLOOR, THATS WHY YOU ETCHED IT!! SEALING IT WILL NOT LET YOUR STAIN PENATRATE.
Let it dry thoroughly and then prime one more time. Then after it's dry I would go ahead and paint it. While the primer is thin the paint (not stain) is very thick and should cover, but I would prime one more time just to be certain of adhesion.
the answer above is correct, bu let me add - make certain the primer is stirred or shaken before use, if the label says to do so.
a second coat should take care of the problem and you should have a good looking floor in no time.
hope this helps.
Iv,e been a professional painter for the past 27 years and priming a garage floor is not part of painting a floor. you are using Behr so i assume you got it at Home depot. They probable sold you a concrete primer as in ...concrete walls. When you paint a concrete floor you want the thinnest possible profile for the entire paint film so you do not create a cushion and when the coating has the added thickness of primer it starts to dent in (as seen under a microscope ) and this is where paint failure begins.
Primer of any sort does not have to block discoloration of any kind to be a good primer. It only needs to seal the surface to be painted to allow for adhesion of the paint.
Concrete primer is a special situation. It is normal for it to be very runny and it will cover a great deal more per gallon than traditional paints. It doesn't sound like you did anything wrong to this point. Also, there is nothing to indicate that the primer has a problem. Masonry primer will adjust the ph of the concrete and seal it, generally will not block color variations.
Do not give the primer a second coat. Again, it is not designed to block the color variations from stains. A second coat may or may not cause you problems, but it definitely will not help.
The only possible misstep I see here is concrete floor paint generally does not require a primer. I have not worked with Behr paints, it is possible that theirs does. In any case, I am fairly certain priming the floor will not hurt anything as masonry primer does not build a film. Just a bit of extra work and money.
I think your paint will be fine. I would be surprised if the oil stains migrate through. The cleaning should have taken care of any surface oil, what you are seeing should just be a stain where the oil soaked into the concrete. It will be nearly impossible to remove these deep stains, especially after primer so you really don't have much choice but to give it a try.
When my garage floor was laid I let it dry (cure) for about 4/5 weeks and used a sealer before the primer and then a good floor paint made for concrete.
It's probably too late to do most of that now, but if any parts of the concrete show up bare I would certainly try a sealer before the primer and paint.
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