Look for copper naphthenate solutions at home improvement and paint stores.
Fixing fence posts to concrete wall.
Set posts then.
If the post is not plumb with the level sitting on the face of the post then loosen relevant fixings and insert packers between gate post and wall and repeat until face of gate post is plumb.
Core drill holes through concrete.
How to install a fence mounted to concrete surface mount fence post with anchor bolts.
12mm x 100mm thunder bolts masonry depending on size of posts would do fine.
When installing a fence on an existing concrete pad some fence installers prefer to.
Use a sledgehammer to break up the concrete around the old post.
Step 3 remove the old post.
If you have an existing concrete slab and you want to mount fence posts.
In this video driveway dudes ross shows you how to easily fit and secure a post to a concrete block wall.
Once plumb re tighten fixings and check for plumb once more.
Drill hole in the post and the wall the same size usually 6 5mm no need to countersink the head they will just pull in flush some about 120 140 should be fine posted 4 years ago.
Alternatively if you did not want the bottoms of the posts covering your wall you could have collars on the posts which would then be bolted to the top of the wall.
Make the hole large enough to ensure you can get a good swing at all sides of the concrete pier.
But yes normally you would want to dig and post crete them in.