I have a cement porch in front of my house that had been painted a while back by the prior owner. After cleaning the porch floor and applying a good exterior primer, I applied 2 coats of Benjamin Moore exterior floor and patio paint- the label says Epoxy Reinforced Latex Enamel/Satin finish- after a couple of days I noticed the paint bubbling up in some spots-it bubbles worse if the porch gets wet. It has been very humid in my area. What did I do wrong? And what can I do to get this porch right? Thanks for your responses.

 

Is the old paint staying put? If it is coming off down to the concrete I would suspect dampness in the concrete, if it is bubbling off the old paint I assume there was an adhesion problem. Was the primer compatable with the finish? I would try to fix the affected areas. If it continues you may need to strip and start over. Wish you luck

 

painting concrete is difficult at best, and requires primers/paints designed specifically for the task. the primer and topcoat also have to be compatible, but more than likely your primer is not compatible with the concrete or the paint already on it. Check the can or call the manufacturer.

-art-

 

what primer did you use?? and what was underneath the primer?

 

1. Exterior concrete needs to be pressure washed with 3500 psi and a 15 degree tip to get it really clean. You'd be suprised at the difference.

2. You needed to etch the concrete with diluted muriatic acid. Then neutralize the acid with diluted (10 parts water, 1 part ammonia) ammonia.

3. No exterior primer will work very long on concrete.

4. The epoxy paint should have been enough, but check with the mfg (prep instructions s/b on the can).

What did you use to clean the porch? Was it dry before applying the primer?
Was it bare concrete or did you take up a carpet or other surface?