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Thread: Retaining wall

  1. #1
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    Default Retaining wall

    Question for those familiar with retaining walls and fences. I have someone who needs to have a new fence installed. Because the property next door is a rental/foreclosure property, she wants some added fence height as well as barrier for trash and debris from coming onto her side. On her side she plans to install a raised flowerbed.

    The current mode of thinking is to run a footing and 2 block high cinder block retaining wall with steel fence posts set into the solid filled blocks with a 6' wood fence on top of it.

    The question is, how deep and wide must the footing be to support the two rows of block and a 6' solid wood fence? My concern is wind shear resistance, not weight or settling of the block. We do not have frost here, so that is not a factor. Soil is rock hard clay in the summer. In the winter, only the top few inches get a little mushy, and it's only those areas that have been amended to any degree.

    Another reason for the footing and retaining wall is to keep whatever garbage the neighbor plants or lets grow from rooting over into my friends property, as all of the scrub trees and shrubs do now.

    Thoughts?
    I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!

  2. #2
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    Default Re: Retaining wall

    Quote Originally Posted by jkirk View Post
    more than 2 feet, ive had to fix fences where the posts were set into 16" of concrete and they still blew over, the more concrete the merrier. and if theres extra concrete simply fill up canuks lunch box
    Geez --- funny boy
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  3. #3
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    Default Re: Retaining wall

    Quote Originally Posted by A. Spruce View Post
    Question for those familiar with retaining walls and fences. I have someone who needs to have a new fence installed. Because the property next door is a rental/foreclosure property, she wants some added fence height as well as barrier for trash and debris from coming onto her side. On her side she plans to install a raised flowerbed.

    The current mode of thinking is to run a footing and 2 block high cinder block retaining wall with steel fence posts set into the solid filled blocks with a 6' wood fence on top of it.

    The question is, how deep and wide must the footing be to support the two rows of block and a 6' solid wood fence? My concern is wind shear resistance, not weight or settling of the block. We do not have frost here, so that is not a factor. Soil is rock hard clay in the summer. In the winter, only the top few inches get a little mushy, and it's only those areas that have been amended to any degree.

    Another reason for the footing and retaining wall is to keep whatever garbage the neighbor plants or lets grow from rooting over into my friends property, as all of the scrub trees and shrubs do now.

    Thoughts?
    Is this raised flower bed going to be against the fence and along the full distance and how much will it be raised ?
    "" an ounce of perception -- a pound of obscure "
    - Rush

  4. #4
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    Default Re: Retaining wall

    Quote Originally Posted by canuk View Post
    Is this raised flower bed going to be against the fence and along the full distance and how much will it be raised ?

    • The wall will be two blocks high, approx. 16".
    • The fence will be on top of the wall.
    • The raised flowerbed will be the length of the fence (approx 100' ), dirt level in the bed would be 8" to 12" deep, well below the top of the block to prevent damage to the fence.

    My major concern is wind shear pushing the fence/block wall over, the footing would need to be resistant to that force, not weight or frost heave.
    I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!

  5. #5
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    Default Re: Retaining wall

    So the top of the fence will be 7'6" above the ground.
    I would probably use 4 or 6 inch ground holes about 2 - 3 feet deep wth the vertical posts imbedded into the concrete --- spaced 6-8 feet apart.
    In your area you probably get away with the footing for the block wall on grade or fairly shallow --- either way you could also tie the block wall into the post piles.
    The stress would be on the posts and concrete pillars and not on the wall.
    "" an ounce of perception -- a pound of obscure "
    - Rush

  6. #6
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    Default Re: Retaining wall

    Quote Originally Posted by jkirk View Post
    can you build it so it steps back into grade on a taper so it would be stronger against the force of the ground
    What?!?! No! Huh? What?!?! If I'm reading your post correctly, you're referring to perpendicular "legs" on the wall that would prevent lift/tilt? That might be possible, but since there is really no earth to pin into, overall I don't know that it would do much good, particularly since they could only be installed on one side. That is, if I'm reading you right.


    Quote Originally Posted by canuk View Post
    So the top of the fence will be 7'6" above the ground.
    I would probably use 4 or 6 inch ground holes about 2 - 3 feet deep wth the vertical posts imbedded into the concrete --- spaced 6-8 feet apart.
    In your area you probably get away with the footing for the block wall on grade or fairly shallow --- either way you could also tie the block wall into the post piles.
    The stress would be on the posts and concrete pillars and not on the wall.
    This just might work. I am planning on using metal posts, similar to the PostMaster brand (think "U" shaped channel with nailing flanges along each side ). Those run about 7' or so in length. They would be placed just under 8' o.c. within the block. That just might be enough to keep the fence vertical. It probably wouldn't hurt to run at least one row of rebar either at the footing or between the blocks to tie the wall to the post to help prevent cracking of the wall at the post connections.

    So, when are you picking up jkirk and heading down this way to help put it all in? I'm sure I can get the girlfriend to spring for a beer or two for your troubles.
    I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!

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