1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

Building piers on top of a wall

Discussion in 'Building' started by petej42, 29 Jul 2019.

  1. petej42

    petej42

    Joined:
    26 Jan 2016
    Messages:
    38
    Thanks Received:
    0
    Country:
    United Kingdom
    Hi.
    I'm after a bit of advice on building some brick piers. I have a concrete block wall at the rear of my property. It varies between 3 and 4 foot tall and is 1 block (9 inches) wide.

    I want to increase the height to 6 foot all along.

    My idea was to build some brick piers on top of the wall and install hit and miss panels in between(it can get quite windy). Would there by any problem with building the piers directly on top of the wall? My thought was either 1 1/2 by 1 brick or 2 by 1 bricks. The existing wall has been up several years and has no sign of movement.

    Any advice would be gratefully appreciated
     
  2. noseall

    noseall

    Joined:
    2 Feb 2006
    Messages:
    34,993
    Thanks Received:
    2,197
    Location:
    Staffordshire
    Country:
    United Kingdom
    Lol. 9" piers with panels between will sail away in the next wind.
     
    • Thanks Thanks x 2
  3. Mobo_14

    Mobo_14

    Joined:
    5 Jun 2019
    Messages:
    45
    Thanks Received:
    11
    Country:
    United Kingdom
    2d8c5bbe-768a-494f-b83e-596b7b0769a8.jpg Done something kind of similar but had to bed 4x4posts in at the back of the piers along the wall.

    As has been said strapping it directly to a 9" butt wouldn't bode too well in high winds
     
    • Thanks Thanks x 1
    • Like Like x 1
  4. petej42

    petej42

    Joined:
    26 Jan 2016
    Messages:
    38
    Thanks Received:
    0
    Country:
    United Kingdom
    So to clarify, the problem would be with the panels tearing themselves out of the fixings rather than the piers themselves failing. I am planning on building the panels myself they would be 18 X 95 mm hit and miss boards with 50mm gaps running either side of 25 x 100 mm batons running top and bottom with multiple anchors to the piers. Maximum 900mm in height above the top of the wall and 1.8m in length

    Similar to this
    https://www.stfencing.co.uk/product/hit-and-miss-windproof-fence-panels-flat/
     
    Last edited: 30 Jul 2019
  5. ^woody^

    ^woody^

    Joined:
    3 Sep 2006
    Messages:
    26,827
    Thanks Received:
    3,329
    Location:
    West Mids
    Country:
    United Kingdom
    No the piers fail.
     
    • Thanks Thanks x 1
  6. Notch7

    Notch7

    Joined:
    15 Sep 2017
    Messages:
    13,561
    Thanks Received:
    1,059
    Location:
    Sussex
    Country:
    United Kingdom
    Wind will still exert lots of load on those panels, although the gaps will help release pressure.

    Brickwork is strong in tension but has little lateral strength.
     
    • Thanks Thanks x 1
  7. tony1851

    tony1851

    Joined:
    23 Feb 2012
    Messages:
    9,228
    Thanks Received:
    1,384
    Location:
    Manchester
    Country:
    United Kingdom
     
    • Thanks Thanks x 1
    • Like Like x 1
  8. Mobo_14

    Mobo_14

    Joined:
    5 Jun 2019
    Messages:
    45
    Thanks Received:
    11
    Country:
    United Kingdom
    In the link you sent looks like concrete fence posts being used which would also work (y)
     
    • Thanks Thanks x 1
  9. noseall

    noseall

    Joined:
    2 Feb 2006
    Messages:
    34,993
    Thanks Received:
    2,197
    Location:
    Staffordshire
    Country:
    United Kingdom
    The piers in the above image are doing the square root of feckall. They are being held up by the fence.

    The piers will fail. Miserably and with consequences if they are adjacent to a footpath.
     
    • Thanks Thanks x 2
  10. Mobo_14

    Mobo_14

    Joined:
    5 Jun 2019
    Messages:
    45
    Thanks Received:
    11
    Country:
    United Kingdom
     
    • Thanks Thanks x 2
  11. Leofric

    Leofric

    Joined:
    9 Nov 2018
    Messages:
    1,657
    Thanks Received:
    139
    Country:
    United Kingdom
    o_O bwk is strong in compression but how do you work out bwk is strong in tension ? - what about the mortar joints ! Bwk has little lateral strength :!::?:
     
    • Thanks Thanks x 2
  12. petej42

    petej42

    Joined:
    26 Jan 2016
    Messages:
    38
    Thanks Received:
    0
    Country:
    United Kingdom
    Thanks for the advice everyone, been really useful. So now I'm a bit stuck. Brick piers are obviously out of the question (unless there is some way of reinforcing them). Can anyone suggest an alternative that would be more suitable. Ideally I would like the fence to sit on top of the wall as it looks tidier. I have seen examples on the web using thunderbolts and bolt downs for wooden fencing posts on top of the wall and other options which involve fixing wooden posts down the face of the wall and attaching the panels to these - are wooden posts really stronger than brickwork under these conditions?
     
  13. Charlie George

    Charlie George

    Joined:
    16 Mar 2018
    Messages:
    129
    Thanks Received:
    20
    Country:
    United Kingdom
    Wooden posts will flex in windy conditions, you could use cranked metal posts or extend footing in wall and build bigger pillars tied into existing wall, make pillars at least 1 1/2 brick square, and drill rebar into centre of pillar and concrete.
     
  14. tony1851

    tony1851

    Joined:
    23 Feb 2012
    Messages:
    9,228
    Thanks Received:
    1,384
    Location:
    Manchester
    Country:
    United Kingdom
    Under high wind, a 1.8m high 215 thick brick wall with no piers will almost certainly fail before a 1.8m high timber fence with 100 x 100 posts @ 1.8m c/s (assuming the posts are well-concreted in).
    Why not set timber posts in concrete immediately behind the wall @1.8m c/s without any mechanical fixing to the wall, and put horizontal timber runners between the posts, and fix vertical laths to those. The idea being that the masonry and timber are separate and there is no additional stress being put on the wall.
     
    Last edited: 31 Jul 2019
  15. noseall

    noseall

    Joined:
    2 Feb 2006
    Messages:
    34,993
    Thanks Received:
    2,197
    Location:
    Staffordshire
    Country:
    United Kingdom
    Yes because they flex before they break.
     
    • Thanks Thanks x 1
Loading...

Share This Page