I sure hope not. I like to paint, and I change paint colors often. I have no idea how many coats on this house. It was built in 1966/68, so pretty sure there are many coats. Walls still look good.

Do they have paint stores in Egypt where you can go and ask your questions to a paint person?

As what you've described " first scratched off all the old paint, then they treated the wall with primer, semi-paint and some thing that is like a hardener to make the wall smooth et. Then they do the paint color" as this doesn't sound like it's just painting a wall. Like why did they scratch off the old paint, and what does scratch mean? Was it done to the entire wall or just spots?

You know, everyday I am amazed at how things are done here, it is so foreign to me. Apparently they scratched off all the paint off of all the walls on my big high ceiling apartment. I do not understand this. Why not just get some primer on there then do the paint color? And the last step before the paint color was that medium gray scib. but good to know the consensus here is that the paint is not gonna “fall off” just cause i painted it three different colors. I find that weird.

I should add that my old contractor is the one who did the paint and he was the one that said that from

now on anytime I want to change paint colors, i just need to paint the new color over the old one. the new contractor who is taking over my place is the one that said these extra layers in the kitchen are not going to last and i will see the paint fall off in a few months to a couple years or so. :-/ strange thing to say as when i was living in the states, i was renting in nyc where they painted my apt everytime a new tenant came. That thing was painted a million times and it looked fine.

I'm wondering if you have plaster walls and they did a scratch coat of plaster on top of the wall and perhaps you are thinking that they scratched the painting off instead?

I wondered if they were plaster, too. It sounds like your new contractor may be assuming the old contractor used a different method of coating the plaster. However, the original contractor could have sealed and primed the plaster well to prevent the problems the new contractor is describing. Is it possible to find out exactly what was used, down to the primer, so you can check the specifications yourself?

They scratched all old painting off. But actually, in the kitchen they did not. The kitchen had ceramic tiles from floor to ceiling and they had to do concrete to create the new walls then do all the other steps from there to make a smooth wall

Regardless of the paint, do you know if the walls are plaster, drywall, or concrete?

Concrete underneath

Painting concrete is different from painting drywall. There are methods of painting/coating that allow the concrete to remain porous, such as mineral paint, and methods that completely seal the concrete. There are also lots of different kinds of plasters/textures that can be applied over concrete, and people seem to use different terms and names interchangeably and even incorrectly, like lime, Roman, or cement plaster, and even Tadelakt. Its possible the change in color from what you selected is because it’s being formulated for a different paint, like concrete paint. I would document each step and what they used, and then take that information directly to the manufacturer for instructions.

When in Egypt, do as the Egyptians. What your Egyptian contractor is describing is known as spalling.

The locally available materials and construction techniques are different in Egypt than in the western world. If you have noticed, in the USA, there are many layers in the exterior of a home, designed for moisture control and insulation. I don’t know what your materials are, but it appears that there is a moisture control issue. That is why they had to scribe/scratch the paint, to get rid of excess paint and to create a increased surface area (on a micro level) to have better adhesion between the new and old layers.

The Jotun Fenomastic is a high quality acrylic paint. With all the layers you are describing, it would effectively create a thick impermeable layer on top of your surface (think of it as being similar to covering your wall with plastic). Water goes from a liquid to a vapor, and that vapor expands in proportion to the temperature. When the moisture builds up between the wall and the impermeable surface, it causes spalling.

Believe what your Egyptian contractor is telling you. He may not know the technical reasons for the problem, but he knows the results. You are very limited by the materials of construction. My recommendation is to use lots of lighting fixtures with LED bulbs, which are much safer than incandescent, fluorescent or halogen. Halogen is the worst for safety, durability and overheating and should be avoided. Hang some mirrors to bounce the light around. Learn to live with the dark color, or prepare to pay for more scratching off old paint in hope that you can buy a lighter color hardener. Since I am not familiar with your locally available materials, I don’t even know if that is a possibility.

https://www.thebalance.com/what-is-spalling-1798631

https://www.energyvanguard.com/blog/75130/What-Happens-When-You-Put-a-Plastic-Vapor-Barrier-in-Your-Wall

Wow, thanks for your thought out response. :-) Can I ask, what is a lighter color hardener? Unfortunately, today they painted over the darker color to put the color I originally chose. So it's done. I will wait to see in the coming months or a year if the paint will fall off like they say.

It sounds like a two component polymer of some kind, and there are many kinds. The point is: it is already done.

To answer your question about “what is a lighter color hardener”, depending upon the polymers used, the color might be an inherent property of the material, or there might be tint added. An example of this is the (one component) crack filler that is pink while it is drying, but dries white so the painters knows the area is dry enough is to paint over it.

Here’s an article on repair of old fashioned plaster walls, which are not as easy to work with as modern gypsum board walls:

https://brooklynplasterrestoration.com/diy-plaster-repair-mistakes-to-avoid/