Fence construction - mounting posts on uneven sandstone wall?

Embedding behind the wall is unfortunately out of the question. The terrain is filled up and will settle over time, causing the fence to sag. The landscaping contractor (who built the wall and filled it up) strictly advised against this and said that the posts must definitely be connected to the wall, maybe by screwing a post base to the wall from behind.

So I spoke again with the fence builder on site and he said: nonsense. Best to core drill into the wall, 20cm deep / 12cm diameter, shorten the posts and embed them in concrete, that will hold. Now I am looking for a suitable core drill for sandstone (any suggestions? There are a total of 12-15 holes) or I will have a company do it...

. So now I'm looking for a suitable core drill for sandstone (any suggestions? There are a total of 12-15 holes) or I might have a company do it...

Hello Changeling

A company charges a lot of money for that. For 12-15 holes you should expect around a thousand euros.
If you don't have two left hands, do it yourself. Ebay Classifieds is well suited for that. You can get a core drill with a matching diamond drill crown for around a hundred euros for 24 hours. But look for someone who gives you the total price including wear of the drill crown. Better 20 euros more than ending up paying a lot for the wear afterwards.

Steven

Best to core drill into the wall, 20cm deep / 12cm diameter, shorten the post and concrete it in,

Keep in mind that you then have to build some kind of support frame for each post, e.g. from roofing battens, so that in the end all posts are leveled in 3 axes.
Alternatively, wedge it in the hole until the concrete / rapid cement / grout hardens and the post can no longer move.

A company charges serious money for that. You should expect to pay around a thousand euros for 12-15 holes.
If you don’t have two left hands, do it yourself.

Uff... so it’s not something you can just do quickly. Unfortunately, here in the area there are no core drilling machines available on eBay Classifieds or erento. And I didn’t want to spend another thousand for a fence that costs a little more than half of that...

Is it really that complicated?

Would it perhaps be an option to fix the post to the stone at height with L- or S-brackets and encase it with concrete, so that we’re back to the previous variant (embedding it in concrete behind the wall) – only that the post can’t sink that way? Or will frost still push it out / can it still sink that way?
Seen from the side like this:
[ATTACH alt="Pfosten.png" type="full"]44552[/ATTACH]

// Addendum: I spoke again with the landscaper. He says: Two clamps per post and additionally fix the lower part of the post with a screw through clamp/post/stone. If necessary, a bit of concrete around it as I just suggested above. That should be completely sufficient, costs and effort manageable. Sounds like a plan!
[ATTACH alt="44304-Wandanschlussschelle-60x40mm-anthrazit-grau_600x600.jpg" type="full"]44553[/ATTACH]

He means: Two clamps per post and additionally fix the lower post with a screw through clamp / post / stone. If necessary, a bit of concrete around it.

It's not about securing it tightly! It's about all the posts being aligned.
How do you screw your clamp/angle bracket to a "crooked" stone?

Hello Changeling

to make it neat (you will regret it for years) you have 2 options:
1. Core drilling
2. You have the posts welded onto a suitable iron rail, hot-dip galvanized everything and attach the construction horizontally onto the stones. But you will also have to drill proper holes in the stone wall.
Everything else is not so great.

Steven