Attaching iron pipe to concrete wall

[Pokereve]

Hello, I am going to build a fence and I need to attach iron pipes (48mm diameter) into a concrete wall that marks the property boundary.
What's the easiest way to secure them? How big should the holes be, maybe 52mm? Plastic padding? Cement?

(In the picture, you can see the old posts and the wall, we're missing 10 posts, and I'm planning to put new ones there)

Kind regards, J

 

[rävlyan]

If you have the opportunity to drill about 60 mm deep and at least 300 mm, that's good, there is space to pour in sluring (a thin concrete mix almost like water, mix cement and fine play sand, no coarse stones) to flow down between, then you should make notches in the pipe and bend out small wings at the bottom to make them attach well. They act like small barbs that hold the post so it can't lift or rotate, and since it's a pipe, you can fill some concrete inside the post as well. Before casting, you dampen the hole, as sluring tends to dry quickly and then it won't flow down as it should, also tap the pipe as you fill it. To get the post plumb, set four small wedges and align it, maybe you can use really narrow wedges and pour sluring between them.

 

[Pokereve]

If you have the possibility to drill about 60 mm deep at least 300 mm, that's good, there is room to pour down sluring (a thin concrete mixture almost like water, mix cement and fine play sand, no coarse stones) as it's called to flow down between, then you should make notches in the pipe and bend out small wings at the bottom to make them stick well. It becomes like small barbs that hold the post so it can't lift up or spin and since it is a pipe you can fill some concrete inside the post as well. Before casting, moisten the hole, sluring has a tendency to dry quickly and then it doesn't flow down as it should, and tap on the pipe when you fill it. To make the post plumb, you use four small wedges and align it, maybe you can have really narrow wedges and pour sluring between them

Thank you! Just one question, what dimension for the drill hole would you recommend? If I'm going to bend out edges, the hole will have to be quite large! Time to rent a core drill machine...

 

[rävlyan]

You need at least 5 mm of space between the pipe and the concrete wall; it's a bit thin for the slurring to flow down, preferably 10 mm if you can. That way, there is room for a little bend at the bottom. It doesn't need to be 10 mm out; a couple of mm and slots are enough.

The slots can be made preferably with a grinder. This creates some space for the concrete in the grooves, which prevents rotating and bending upwards, and a dash inside the pipe at the bottom. Don't forget to wet the holes; you can preferably fill them with water and then blow or go down with a cloth and absorb the water. Tap on the pipe so the concrete flows down.