I painted an interior concrete floor, but now I am getting large bubbles in a few areas. How do I fix this?

Question

I used concrete preimer, matte latax paint and the floor was cleaned well before starting any work

Answer 1

I hate to break the news to you but it sounds like you have one of two issues. Either you have a problem with moisture coming through your floor (and used an inadequate primer). Or you didn't prep the surface by roughing it up first. Both will cause delamination, but bubble formation is usually the result of moisture in the floor. How do you fix it? You could try to remove only the bubbles and repaint those areas, but you're probably going to see more issues. The BEST way to resolve it would be to strip the entire floor - rough up the surface with a grinder, acid etch or bead blast. Then clean any fines or neutralize any acids, finally hit it with a penetrating sealer... a silicate or siliconate (see http://www.mightyseal.com they can tell you the difference). After that you should be free to paint it. Lastly, if you have very serious moisture issues you might try www.aquafin.com their SG-2 product seems to hold back some serious moisture, but its pretty pricey.

Answer 2

Concrete leaches moisture and there is nothing you can do about it , less sealing it but even that does not work depending on the moisture content in the soil surrounding your home. Your paint is bubbling up due to the moisture from the concrete wicking up below it.
The best thing you can do is stain it with a acid wash that is available at Lowes or Home depot for garage floors. The staining process can be quite elaborate or just kind of mottled depending on your artistic abilities.
Here is a site to give you an idea about staining concrete. Oh yes, sorry but you'll have to remove the paint you put down before tackling staining.
http://www.acidstainconcrete.com/options.html

Also found this. You should have used an epoxy paint.
http://www.diynetwork.com/diy/hi_outdoor_structures/article/0,2037,DIY_13927_2370969,00.html

Answer 3

Wasn't cleaned throughly enough, and latex paint is a bad choice for the floor. Scrape it all up and start over.