ᐅ Correctly Installing or Repairing Exterior Plaster / Render

Hi all,

I have the following problem: on the exterior wall of our garage (with an attached staircase on the right side), the plaster keeps cracking during the winter. Until now, the plaster applied by the previous owner apparently extended all the way down to the ground, or even the steps. Last year, with good intentions, I installed base tiles along the staircase in the hope that it would improve the situation. In fact, the problem is now worse than ever. At many spots about 20 to 30cm (8 to 12 inches) above the base tiles, there are large areas of damaged plaster.

How should I correctly approach this to stop it? Should I use base tiles or not?

This is what I had in mind:
- Remove the base tiles
- Create a 2-3 mm (0.08 to 0.12 inch) joint between the exterior plaster and the ground
- Insert a sealing cord
- Repair the damaged plaster areas
- Paint over
- Do not install base tiles again

Could this work? What is the easiest way to create the joint?
Would you recommend adding any drip edge or similar detail?

Markus
Here are some pictures of the mess...

Thank you very much in advance.