Advice sought on outdoor wall: is my plan sound?

[Bluegill]

I hope fellow Wet Canvassers here can give me some advice and guidance. I’ve reviewed some old threads here on the topic, and I think I have a plan, but I’d like to get some comments on my specific situation in case I’m missing something!

I have been asked to paint the outdoor concrete wall, pictured:




The whole length of the wall, and the outbuilding in the middle, will be painted. The idea is to make it look like the stone exterior of the building next to it:



I’ve been told that the paint that is already on the wall is an exterior latex. It looks like a semi-gloss. On the low part of the wall only has a thin layer of white, but the concrete shed has a thick coating of multiple layers.

The wall is cracked and broken in spots. The surface of the building is mostly intact, but there are a few areas where the thick paint is peeling with crumbling pockets of cement underneath.



This is at a school where my children go. Finances there are tight, and I love the school, so I’m going to try to keep things as low-budget as possible. At the same time, I’m worried about spending a lot of time and effort and not having it last; I don’t want it to flake and peel after six months!

So here’s what I’m thinking I should do:

1. (The maintenance guy just power-washed the wall - haven't seen it since, but I'm hoping all the green stuff is gone)

2. I’ll go over the whole thing with a putty knife and scrape away all the loose paint I can find

3. Coat it all with a coat or two of exterior primer, like Kilz.

4. paint the pseudo-stonework with exterior house paint.

I’m not especially concerned about the cracks; I can just work them into the stonework scheme. It’s exposed to rain, but never gets direct sunlight.

Does this sound like a reasonable approach? I’ve never painted an outdoor mural, and I’ve never painted anything even close to this size. Any suggestions you could give would be appreciated!

[vmrs]

As long as the exterior paint and primer are an acrylic based latex, so it fluctuates with the concrete expanding and contracting, it should be alright with a good wall.
But it looks to me like there might be some structural issues with that wall, it's a retainer but it's an older one and it looks like the hole in your last photo is caused by incorrect seepage (or it could have been dinged by a car, hard to say). The dirt shouldn't be over top of it, where the hill comes down either.
If you know someone who could give you free advice like a contractor or bricklayer you might want to ask them if it's worth doing a decorative paint job on it or if you should just paint it in a more subtle solid to blend with the stonework on the adjacent building.

[mburrell]

What kind of paint is on the wall alkyd or acrylic? Test by using alcohol on a rag or cotton if it lifts color it is acrylic. Zinsser 123 is a good water base primer it will go over both types of paint and give a good surface to paint on. I notice mold on surface you can get a anti-fungus additive for your paints but you might be better to add it to your clear coat at the end. Sealkrete goes on milky white dries clear with a gloss finish. hope this helps.

[eggnshells]

Hi, If it was me, I would still do a light sanding with an electric sander just to give the primer something to adhere to. I would also add some of the grout color to the primer so that step is taken care of, then go ahead and do the rock pattern. Kilz seals so mold and fungus can't show through. Then depending on the paint you use for exterior as some can have the sealer already added in or you can mix it in instead of sealing everything later on. Hope to see your photos when done.

[Bluegill]

Thanks to you all for your comments and suggestions. The white on the wall is a latex paint.

After I scraped the wall, someone else power washed it than hit it again using some sort of hydrochloric acid cleaning solution. I didn't notice much difference. Then I used a Deal Chicken coupon for Porter Paints (a well-regarded regional brand) to get a good mold-resistant primer in gray. I wore my arm out priming the wall. Then I got a couple of colors in Porter Paints and some Glidden paints for mixing. Trying to keep costs down, I got four colors altogether (an orange color, blue-gray, white, and black.) I've been painting for a while, and it's coming together. It's been sort of nice working there in the evenings in the 95-degree heat, with just the bluejays and the mosquitoes...sweaty, but peaceful. On the actual painting, I've got about 15-20 hours in. I'll post some photos soon.

Thanks again!

[Bluegill]

Here is my progress so far.

I'm going back tonight to work some more until it gets too dark to see what color I've mixed.

[vmrs]

Wow, that looks great!!

[debsn2paintn]

Boy that's a lot of work and it's paid off... looks wonderful

[Bluegill]

Thanks! I’ve been getting compliments on it from school employees, and so has my wife, who works there. She’s been telling them, “Oh, he’s not close to done! If you think it looks good now, wait until he goes back and shades everything in!” Meanwhile, I’m standing there sweaty and tired, thinking, “Uh…let’s not over-sell this…”

[Bluegill]

Well, I'm calling it done, even though I still have a little work to do when I get the chance. I'll probably add some highlights to the trim on the window, and double check to make sure there aren't any accidental suggestive shapes ( ) in the stones, and at some point I might paint the top of that back wall that I didn't paint because it was so porous and overtopped by dirt.

I'm pretty pleased with it, overall.

[Autumnwillow]

Looks so much better, great job!

Michele

[Bluegill]

Thank you!

[vmrs]

Bravo, that is a lot of work and it looks fantastic!

[RainySea]

wow, that came out great. love it. Must have taken many, many hours.

[Bluegill]

Thanks! Yes, it felt like it took forever. But I don't really feel like saying that when I see some of the mural work that gets posted here--huge, beautiful, fabulous stuff!