Fixing timber post to concrete fence post

Discussion in 'Builders' Talk' started by lincoln7890, Aug 1, 2020.

  1. lincoln7890

    lincoln7890 New Member

    Hi all,

    I'm after some advice please. I'm looking install a set of softwood driveway gates, one side would be against a brick wall and the other against an existing, concrete fence post (which is 90mm wide, 1100mm thick). There are no pre-existing holes to use. I'm looking to attach some 4x3 timber as posts, from which the gates will be hung.

    I've done some 'Googling' and aware that concrete posts can 'crack' apparently, so planning to start with a 5mm drill bit and work up accordingly, which I hope will minimise the risk of any blow-out/cracking.

    In terms of fixings, for the brick wall side I'm planning to use 120mm masonry bolts, countersunk into the timber. When it comes to the concrete post, I'm not entirely sure which way to go, and would be grateful to know if anyone has done this already. I could probably use coach-bolts, but conscious that'd mean drilling all the way through the post, circa 3 times... maybe the masonry bolts I'm going to use on the brick wall would be okay too?

    I'd welcome any thoughts/suggestions!

    Thanks in advance.
     
  2. ramseyman

    ramseyman Screwfix Select

    I think you’ll have a heck of a job drilling holes in the concrete post. If you can’t dig it out and replace it with a decent concrete,wooden or metal gatepost why not consider encasing it in 6 by 2 timber, ripped down as necessary, bolted together with coach bolts and take it from there.
     
  3. Aj 2012

    Aj 2012 Member

    Is it just plain concrete? Normally they have rebar in supporting. When you drill it , the masonry bit will bounce of the rebar! You may be able to drill in ok but you need luck on your side!

    If you can then I would use thunderbolts / masonry screws.
     
  4. lincoln7890

    lincoln7890 New Member

  5. Aj 2012

    Aj 2012 Member

    I can't see any images...

    Screws attached will need a 6mm pilot hole if my memory serves me correct however If holding gates I would personally use bigger than those screws such as the ones in your original post or below, 4 on each post equally spaced.

    https://www.screwfix.com/p/easyfix-...teel-concrete-bolts-m10-x-120mm-10-pack/8215p

    These take a 10mm pilot hole and if recall correctly to counter sink them onto the wood I used a 1"/25 Forster bit or a spade bit so the bolt isnt over hanging and you can still get a socket on them.
     
  6. lincoln7890

    lincoln7890 New Member

    That's great - thank you. I'll give those a go!
     

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