Painting - Painting Outdoor Concrete Wall

Hi!

I'm looking to paint an outdoor concrete wall (actually the side of a raised concrete porch.) I've read the articles and other forum posts about painting concrete floors. Does the recommendation to wash the surface with a muriatic acid solution apply to walls too? (since you can't really let the acid sit on the surface.) Do hardware supply shops typically stock it? Is there any particular kinds of paint I should be using?

Thanks much for any help!

Rhodnius, The deal with washing with acid is to etch the dirt and whatever out of the pours so paint/stain/sealer can get a bite and hopefully stay. Its always a gamble for long term durability when working concrete. It wouldn't be a bad idea to etch the wall as cheap and easy as it is to do but in that it isn't a walking/driving surface you could skip it as long as it seems clean. If you decide to use acid it can be brushed on with a plastic bristle brush and will start sizzling and smoking a little when applied. A rinse will finish the washing. Acid can be found at most paint and hardware stores....Mike