Unless you have good reason, asking for an engineer report is probably a step too far.
You describe that the common property wall has cracked tiles. Request the OC to replace th3 tiles. They then have to do it within a reasonable time.
If the committee is on the ball they will also find out why the tiles are cracking and whilst the tiles are being replaced check the waterproofing.
Dont replace the tiles yourself. By doing thst you are damaging common property, and you could then be responsible for any further rectification required.