DIY Home Improvement Forum banner

Basement flood peeling

2K views 6 replies 6 participants last post by  ric knows paint 
#1 ·
The floor of a church was painted and is peeling. We thing the paint under the new paint made have been an oil base and the new coat is water base. Is this why it's peeling? If so, how can we correct this? Do we have to remove the new coat and again, if so, how? Advice is appreciated.
 
#7 ·
Mark,

If your paint is peeling (and I assume it's peeling down to the previous coat of paint) - all loose material will need to be removed before continuing. There is nothing that will successfully bind a poorly adhering coating...

A couple of people have mentioned that improper or inadequate surface prep is to blame...unfortunately, that's true - and I'll get to that in a minute - but first, a couple of things that is probably NOT the cause of this failure.

First, there is no reason to consider an incompatibility between an oil based coating and an acrylic (latex) coating unless the product was a very low-quality, cheap "floor" paint. These 2 systems can work very well together, if the proper surface prep is conducted prior to painting (but that also holds true if you're painting oil over oil).

Second, If my assumption is correct that the paint is peeling to the previous layer of paint, I'm pretty certain you can eliminate ground moisture as the problem. If it were "rising" ground moisture, it would've taken all coats of paint with it - rising moisture cannot bypass one coat and attack only the final app.

Third, it has not failed as a result of no, or improper primer...floor paints do not require primers per se...especially not in a repaint situation. There are acrylic products on the market that penetrate slick, sealed surfaces so a better foundation to provide a better mechanical adhesion of coats, but few companies make, or even recommend that application.

So...it all comes back to surface preparation. High quality acrylic floor paints are very good coatings - even over surfaces painted with an oil (alkyd). The following surface prep steps are absolutely necessary (even if painting with oil)...

The floor must be clean. Over the years, floor paints take punishment beyond that of their vertical application counterparts - even if the floor is only subjected to foot traffic. There is a tremendous amount of stress to the adhesion of a coating when a 200 pound man, wearing tennis shoes, pivots on the painted surface. Dirt is microscopically ground into the film every time a person walks across the floor with any type of shoes...Multiply that now by the number of people that walk across the floor weekly over...how many years? These ground in dirts and contaminants must be thoroughly cleaned by scrubbing surface with an effective detergent such as TSP - then rinsed with clean water to remove any residual film of detergent....

Once floor has been scrubbed clean, rinsed and allowed to dry, sanding with a medium grit paper creates a profile necessary for best adhesion of any subsequent coating (vacuum to remove sanding dust prior to painting).

If there are any areas where the paint has chipped away or peeled to bare concrete, you may want to consider etching the exposed concrete to (a) remove any residual concrete hardeners and to create profile for a better bond, and (b) to neutralize that annoying alkalinity certain to be present in concrete.

And that, as simple and un-complicated as it sounds, is all that's necessary to ensure good adhesion for your next application of acrylic, or any other type of coating.

As is with all coatings, there is a very critical "cure" time for coatings that is different than "dry" time. With either acrylic or alkyds, if possible, give the floor a minimum of 3 days before subjecting to traffic any heavier than light foot traffic - and always, always, choose high quality paints, preferably from an independent paint dealer that is capable of walking you through these problems and solutions. Good luck and let us know how things turn out.
 
#2 ·
If Latex was used on top of Oil based paint, yes it will peel. Also if the old layer was filthy paint will not adhere, or if the floor gets really cold during Winter, it can also cause paint to peel off of it.

The best thing is to remove all paint, and maybe go with a stain on the concrete instead.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top