How to drill and set a steel fence post into a limestone retaining wall?

[Bandicoot]

I want to set a 50mm SHS fence post beside the high side of a limestone retaining wall, but there is a footing course only 350mm down.  The post will be side loaded so needs to be fairly strong, so I was thinking of somehow setting it into the footing course and concreting above that to ground level, but have no idea if this can be done without specialised tools, or if these can be hired?

[Jewelleryrescue]

Ok Hi @Bandicoot 

I think I am  hearing you want to drill intoa   solid footing to  cement a post into?

To  do this  normally you would  use a something like a  hammer drill or  a  jack  hammer to break up hard  footings.

Or   if your  situation  allows  bolt into the footings  with a steel post  bracket  this little  but strong  bracket fixed to the footings and then the fence post sits over the top and is side screwed to the bracket and is surprisingly sturdy.

Australian Handyman Supplies 50 x 50mm Internal Fixing Post Bracket

I/N: 1130411 $4

https://www.bunnings.com.au/australian-handyman-supplies-50-x-50mm-internal-fixing-post-bracket_p113...

Lets  talk more and a  photo of post locatio might help too thanxs

[Bandicoot]

Thanks @Jewelleryrescue.  The existing house fence posts are cemented into 100mm holes evidently drilled into the blocks; I was hoping to do something like that to retain the support strength of the lower footing block without "breaking it up".   If this isn't practicable I'll get one of the brackets you suggest and shorten the post. 🙂

[JacobZ]

Hi @Bandicoot,

What you're proposing sounds possible, but there isn't a perfect way of doing it.

The best way I can see to do it is mark out the location of the post then use a long masonry bit to drill out a series of holes along the perimeter, ensuring you keep the drill bit plumb. Once you've put a number of holes down through the concrete, use a chisel bit to break apart the concrete. The holes will create a weakness in the concrete that will guide the concrete where to break apart. There's no guarantees that this won't cause cracking in the footing elsewhere, but it is the best way I can think to do it.

Alternatively, and likely a better option is to use Chemset to set threaded rods into the footing then attach a 50mm Galvanised Steel Seat Bracket to the rods with a nut and the bracket to the post with a bolt and nut. This will utilise the footing for lateral strength and will require much less work than cutting a square hole to slot the post into.

Let me know what you think.

Jacob

[Bandicoot]

Hi Jacobz,

I used a masonry bit in the way you suggested, but only cut a ~50mm deep "key" for the post and the concrete that was going to fill the hole, because the hole was drying out and my working in it was causing a lot of sand caving; I was going to need too much concrete to fill it back up!  I set a couple of 150mm Ankas 100mm into the top course of blockwork to provide another key for the concrete and compensate for the shallow footing; hopefully that will hold everything together when it cures.  Thanks for your advice.

[JacobZ]

Hi @Bandicoot,

It sounds like a good solution to the problem. Hopefully it works as you had hoped. I imagine it will.

Jacob