Retaining Wall Query

Discussion in 'Builders' Talk' started by Mosaix, Apr 14, 2019.

  1. Mosaix

    Mosaix Member

    Hi

    I have a retaining wall, in some places over six feet high and fifty feet long, made from breeze blocks.

    It's been there since I bought the house (over forty years ago) but there are cracks appearing in it and there's a definite but slight outer lean developed.

    It needs rebuilding. That's not something in my skill-set and I can't afford a builder at the moment. It's probably getting dangerous and I do think I could take it down block by block - maybe to half height. Is it worth while keeping and cleaning up the blocks to save a bit of money on the rebuild or is that not worth the effort?

    I've no idea how much these blocks cost.

    Thanks in anticipation.
     
  2. KIAB

    KIAB Well-Known Member

    Not worth the effort reusing blocks.
     
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  3. robertpstubbs

    robertpstubbs Active Member

    As a general rule a retaining wall should not be more than 3 ft high unless reinforced, and if terraced, retaining walls should be at least 6 ft apart. A retaining wall over 3 ft high should have suitable reinforcement and appropriate foundations to spread the load.
     
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  4. Jord86

    Jord86 Well-Known Member

    Really really not worth the effort.
     
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  5. Mosaix

    Mosaix Member

    Thanks, all, especially the advice regarding the retaining wall height. Although that does leave me with some serious and expensive-sounding problems.
     
  6. Jord86

    Jord86 Well-Known Member

    If it's worth your effort removing and cleaning them, then it's worth the effort rebuilding it yourself, albeit a lot slower than a professional.
     
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  7. Severntrent

    Severntrent Active Member

    Retaining wall height can be any height you design it to be, if its just brick or blockwork the thicker the wall the higher it can go butfondation design will also come into play. As for reusing blocks that depends on what cost you put on your free time, note that there is a market in reclaimed bricks so someone considers it worthwhile with bricks.
     
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  8. robertpstubbs

    robertpstubbs Active Member

    The very fact that the wall is cracking and leaning means it wasn’t properly designed, so just rebuilding it isn’t enough.

    Look at the size of a one tonne bag of aggregate or a one tonne pack of bricks, and then guess how many tonnes will come down when your wall falls.

    What is next to the wall? Buttressing might be a solution.
     
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  9. sospan

    sospan Well-Known Member

    You may want to consider gabions. The gabions will reduce the amount of water pressure behind the baskets. You will be able to use up a lot of the broken blocks at the back of the baskets and just face the visible parts with good quality stone.
     
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  10. KIAB

    KIAB Well-Known Member

    Like my gabions, can step them abit,add some soil & then plant up with some plants which will cascade down & hide gabions.
     
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  11. sospan

    sospan Well-Known Member

    I drove alongside a section the other day, so well done it looked it like dry stone walling until you noticed the mesh. So many pluses over conventional retaining walls and once the base is down, can be installed by relatively unskilled labour
     
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  12. Mosaix

    Mosaix Member

    Thanks, everyone.

    The more I think about doing it myself the more I think it might be a good idea. This side of the wall is a sloping drive, hence the variable height of the wall (from 3 feet to 6 feet). Strangely it is the 3 foot section that has the cracks and is sloping. On closer inspection the blocks from the two areas have differing surfaces so I suspect that it's been done in two stages - the 6 foot section being properly designed, the 3 foot not so.

    The existing blocks are of the two-hollow-compartment variety. Would I have to use the same or would solid blocks do ok? Or doesn't is matter?

    Regarding buttresses - I don't think the drive is wide enough to have buttresses and allow vehicle access.

    Regarding gabions - I'm attracted to the idea but would the width of them involve the removal of a lot of material from the rear of the wall?
     
  13. KIAB

    KIAB Well-Known Member

    The hollow blocks are usually used with rebar & then filled with concrete.

    upload_2019-4-15_10-52-3.jpeg

    Gabions baskets are available in many lengths & widths, just remember though,you will need help moving the larger ones into place..

    https://www.finemeshmetals.co.uk/gabion-baskets
     
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  14. sospan

    sospan Well-Known Member


    And are a real challenge to do properly - physically, not just lifting them in place but up and over the re-bar the organisationally making a mortar mix then a concrete mix to fill then clean out the mixer for the next mortar mix. The last "hollow" retaining wall I did was 14 years ago a vowed I would never do one again .....
     
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  15. robertpstubbs

    robertpstubbs Active Member

  16. KIAB

    KIAB Well-Known Member

    'Ditto'

    Horrible job building walls using them.
     
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  17. sospan

    sospan Well-Known Member

    Surprised they are still allowed to be manually handled as most places set a limit on manual handling at 25kg some of the hollows weigh in at 27kg dry, then lifting that up over the rebar and of course at the point where you are getting tired you are at the bottom of the stack where the blocks are wetter :oops:
     
  18. KIAB

    KIAB Well-Known Member

    Did a 30mtr retaining wall about 9' high with them,about 11 courses, for a building which backed onto a field about 25 years ago, NEVER,NEVER, AGAIN.
    Put in a silly high quote for job,knowing that the chap would refuse it, but other quotes were even higher,learnt a hard lesson that day.:rolleyes:
     
    Last edited: Apr 15, 2019
  19. sospan

    sospan Well-Known Member

    I couldn't even contemplate it now, felt my age a couple of weeks ago when I tried to move some WBP plywood. I couldn't lift it and had to slide it around on some plastic guttering. A few years ago carrying 8x4 by hand even without a board lifter would have been easy. Now, almost impossible :oops:
     
  20. Mosaix

    Mosaix Member

    Hi guys. I hesitate to 'like' your posts where you are describing past sufferings - you have my sympathies.

    If you are saying that the hollow blocks are difficult to handle, even for professionals, then it would appear the solid blocks are more suitable for me, especially as I'm 73 yrs old, although reasonably fit.

    Would the solid blocks, lighter and without re-bar, make a strong enough retaining wall? Or is there a special way of laying them to give them the strength?
     
    Last edited: Apr 15, 2019

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