Another pic : https://files.catbox.moe/7ve71g.jpg
Have you tried adding spiders?
Whats the join? Looks like maybe outside wall to footpath? If so, you'll probably be right to leave it. Fill it with cement or even just sand if the gap annoys you.
Ps, i am not a builder, so yeah treat me like a peanut gallery.
Yes, its outside wall to footpath. Can I use caulk ? Something like this
https://www.bunnings.com.au/poly-450g-vanilla-coloured-caulk-gap-filler_p0104662
You definitely could. I'm always hesitant to use gap fillers outside, just because i don't see them as a long term solution.
But it'll plug the gap for now, and its always easy to replace when it starts looking a bit old and tired in a few years.
You will want to dig out the crack properly first. This is a bit of an art -- take too little or too much away of the weak nearby wall render and it won't look as good. Applying the filler is also a bit of an art if you want its surface to look smooth.
I recommend doing a test run on a small spot somewhere first (that you can dig out again once it has dried). That will help you build confidence and get a working method.
N.B. White filler might be better. I'm not familiar with the product you link to, I think it might be an acrylic based one (water-based cleanup) rather than silicone based, which makes me suspect it's not as hardy but I might be wrong. Test a bit and see if it sets to a nice hard finish (or a weak porous one that stuff might grow in).
That's not structural damage. The wall and the pavement were made separately, there will always be a gap between them. Judging by the rough edge it probably used to look like there was no gap? Someone just decided to make the wall render butt up against the ground, but that only sometimes hides the gap.
The gap will change size over the years due to expansion and contraction (caused by heating, cooling & moisture) and ground movement (including settling).
