Cost effective finish for outbuilding exterior walls

Hi all,

I have a number of outbuildings with exterior walls that are cement plastered and painted with commercial exterior paint. The paint is now in poor condition and needs to be removed back to the plaster, with some cracks also needing repair.

Rather than repainting with commercial paint, I’m wondering what alternatives there are.

I was thinking about some kind of cement- or lime-based finish that could be brushed or applied over the plaster, perhaps something that could also be coloured.

What alternatives have you used, and what would you recommend?

Thanks!

I lime wash. All my house rooms, barn, gate, oven with the same mix.
I use high calcium (more reactive) lime putty that I prepared a few days earlier. I mix it with water using a mixing paddle on a drill.

Three important advices:
1. The consistency should be full fat milk-like, not a creamer. If it's thick, it will flake off. It will seem that it's too thin and application process will be very messy, but this is what works for me. I use a large, natural hair brush 20 cm/8" wide. Since it's messy, please protect the areas/objects that you don't want to paint, as the wash will be dripping from the brush.
2. Do not try to make it perfect with the first coat. Thin mix will not cover everything perfectly. The succeeding touch-up will cover inperfections. For this I use 5 cm/2" brush.
3. Do it when it's cooler, overcast and humid after the rain. 15 C/60 F would be perfect. Shaded interior can be done on a warm, even hot day, but it may need water misting throughout the day. I lime washed interiors on hot, dry days and they also turned out great, but for the outside I would never risk it to do it in full sun on a warm day. If I had to, I would wait for the night.

If it's done properly, it does not flake, nor dust. It looks gorgeous.
I lime washed following surfaces: lime plaster, clay plaster, fired clay bricks, compressed earth blocks, concrete.

I never used any colorants, because the super bright white finish is my favorite and also, because I live in a place that gets 3500 hours of sunshine that needs to be reflected off the buildings.
Mineral colorants would probably work great.

Regarding cost. I do not remember exactly, but half to full 5 Gal bucket of lime putty will do 30 m2/330 sq ft of area. One $25 bag of lime makes 2 such buckets, so $25 per 60 to 120 m2.