Sleeper wall build - advice on drainage please

Hello, I hope everyone is enjoying the lovely Easter weather!

My husband and I are relatively new to gardening and have just moved to a new house. Having become addicted to Monty's programme Big Dreams, Small Spaces, we have become inspired to landscape our garden. I have drawn up a fairly unambitious plan to deal with our lumpy sloped lawn that the builders created! 

The garden slopes up away from the house and we sought advice from a landscaper and the best solution for this is to create a retaining wall at the midway point in the garden and level off each section. The portion in front of the house will be patio, then a sleeper wall built out of timber sleepers, 3-4 steps take us up to the second level with lawn and decking. Each section is flat, resolving the slope.

My question is with regards to making sure we ensure there is drainage for the wall. Is this really important (I think yes?!), if so how to add it?

Is is a case of creating a section between soil on top level and the wall and then filling with gravel? Do we need a drainage pipe or is the gravel enough?
Does the gravel need to sit under the sleepers?
Does there also need to be gravel infront of the sleepers between the wall and the patio?

Also, to fasten the sleepers, should we use concrete or mortar?

Any advice appreciated please! I have researched online but getting a bit overwhelmed by many different methods.

Thank you in advance.

Victoria
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Posts

  • ObelixxObelixx Vendée, Western FrancePosts: 18,782
    edited April 2019
    We used railway sleepers to create several retaining wall in our last garden and theyr'e still standing 20 plus years later.   We did nothing about including drainage but did line the insides with black plastic to help protect them from moisture from the soil.   

    Their own weight was enough to hold the lower wall that separated our parking area from what became a leveled fruit garden tho you may want something more secure if they're likely to be climbed on, walked on or sat on.   For the higher wall that held up what became a level veggie garden, we just planted some sleepers in vertically to hold up the horizontal layers then cut them to height afterwards.  I can probably find you some photos in a couple of days when I'm home again.

    I should add that garden was in central Belgium so serious amounts of rain and some impressively cold winters.  Far worse than anything in the UK.
    "We don't stop playing because we grow old; we grow old because we stop playing." - George Bernard Shaw
  • AlliumPurpleSensationAlliumPurpleSensation Kent Posts: 123
    edited April 2019
    This is my sloping garden which slopes upwards like yours but also left to right.

    We have a main drain and a soak away in the patio, the soak away really doesn't do anything! 

    The previous owners were not gardeners, neither am I really so just trying my best.

    Last summer I dug out a 6 inch channel around the patio  as it had just become full of leaves and a built up of composted stuff which was increasing the soil level.  This is now all filled with gravel and has helped with the drainage.  I also have two larger areas to sweep water to when cleaning the patio but these are planted up.

    Herbs in one side and ferns and hostas in the other.



    If you can put drainage pipes into the garden to collect some of the run off I think this would be good.  My lawn is a mess due to the amount of moss which I think is a drainage issue so I'm just living with it.

    As our slope has the biggest height difference produced by the retaining wall I havent levelled any area further as can manage the mower on the gradual slope.  

    The only exception is one corner which has raised beds for veggies, this is only 3.5m x 2m but was a huge job to level out. I used sleepers for this, only two high and screwed a baton to the back of each and then a stake as it was going into soil and not holding anything back behind it.

    Our retaining wall is on a concrete base which I think is needed due to having such a huge weight behind it.
  • hogweedhogweed Central ScotlandPosts: 3,951
    First of all - how high will the retaining wall be? If you are saying 3-4 steps up then that is only about 600mm ie 2 foot (max up on a step = 150mm ). If so, then your wall would be the same, poss a bit higher and depending on the type of sleeper you get, will need to be somewhere between 4-6 sleepers high (laid on the flat side). You don't use cement or concrete with wood. What you will need is a level surface to lay them on, I would recommend digging down about a foot, a bit wider than your sleeper, filling half the hole with hardcore, then a concrete mix on top so you have a stable surface to build on. 
    The sleepers themselves should be built up with staggered joints. Backfill behind the wall with gravel for drainage. The sleepers will need to be pinned through the height to keep them stable (lots of different ways to do that). Remember to make the sleeper wall with an arm at each end going back into the 'high' bit. 
    Also beware of the effect of changing your levels will have on any existing fences - both on the high bit and the low bit. 
    If you are not good with levels, then get a builder friend to mark them out for you and you do the donkey work.  

    It is perhaps quite an ambitious project for starting off your gardening experience!
    'Optimism is the faith that leads to achievement' - Helen Keller
  • Obelixx said:
    We used railway sleepers to create several retaining wall in our last garden and theyr'e still standing 20 plus years later.   We did nothing about including drainage but did line the insides with black plastic to help protect them from moisture from the soil.   

    Their own weight was enough to hold the lower wall that separated our parking area from what became a leveled fruit garden tho you may want something more secure if they're likely to be climbed on, walked on or sat on.   For the higher wall that held up what became a level veggie garden, we just planted some sleepers in vertically to hold up the horizontal layers then cut them to height afterwards.  I can probably find you some photos in a couple of days when I'm home again.

    I should add that garden was in central Belgium so serious amounts of rain and some impressively cold winters.  Far worse than anything in the UK.
    Thank you for taking the time to reply! I can imagine that there is an element of me being overly cautious but want to get this structure right just in case the worst happens. If not too much trouble would be great to see pics please!
  • This is my sloping garden which slopes upwards like yours but also left to right.

    We have a main drain and a soak away in the patio, the soak away really doesn't do anything! 

    The previous owners were not gardeners, neither am I really so just trying my best.

    Last summer I dug out a 6 inch channel around the patio  as it had just become full of leaves and a built up of composted stuff which was increasing the soil level.  This is now all filled with gravel and has helped with the drainage.  I also have two larger areas to sweep water to when cleaning the patio but these are planted up.

    Herbs in one side and ferns and hostas in the other.



    If you can put drainage pipes into the garden to collect some of the run off I think this would be good.  My lawn is a mess due to the amount of moss which I think is a drainage issue so I'm just living with it.

    As our slope has the biggest height difference produced by the retaining wall I havent levelled any area further as can manage the mower on the gradual slope.  

    The only exception is one corner which has raised beds for veggies, this is only 3.5m x 2m but was a huge job to level out. I used sleepers for this, only two high and screwed a baton to the back of each and then a stake as it was going into soil and not holding anything back behind it.

    Our retaining wall is on a concrete base which I think is needed due to having such a huge weight behind it.
    Hello, thank you for your pics, garden is lovely! I can see you have gravel in front of wall. Do you have any drainage behind?


  • hogweed said:
    First of all - how high will the retaining wall be? If you are saying 3-4 steps up then that is only about 600mm ie 2 foot (max up on a step = 150mm ). If so, then your wall would be the same, poss a bit higher and depending on the type of sleeper you get, will need to be somewhere between 4-6 sleepers high (laid on the flat side). You don't use cement or concrete with wood. What you will need is a level surface to lay them on, I would recommend digging down about a foot, a bit wider than your sleeper, filling half the hole with hardcore, then a concrete mix on top so you have a stable surface to build on. 
    The sleepers themselves should be built up with staggered joints. Backfill behind the wall with gravel for drainage. The sleepers will need to be pinned through the height to keep them stable (lots of different ways to do that). Remember to make the sleeper wall with an arm at each end going back into the 'high' bit. 
    Also beware of the effect of changing your levels will have on any existing fences - both on the high bit and the low bit. 
    If you are not good with levels, then get a builder friend to mark them out for you and you do the donkey work.  

    It is perhaps quite an ambitious project for starting off your gardening experience!
    Hello, thanks for taking the time to reply. I know it is a bit daunting but we are able enough, just need to make sure we have the correct knowledge to complete this task properly!

    Our wall only needs to be 450mm high. I think it will be max 3 steps up to next level. 

    When you say ‘arms’ do you mean tie-back and deadman posts, like a T shape going back into the higher level? Do these need to be just at each end of the wall or all the way along?

    If we add a pipe for drainage behind the wall does it just run horizontally behind or does it need to come out somewhere to flow onto patio in front of wall? If so, where? Scratching my head a little on that point.

    if we place the sleepers on a concrete base how do the sleepers attach to this?

    Thank you!! Sorry if these questions seem really basic but I’ve watched so many videos now and there seems
    to be different techniques- it becomes confusing.

  • NollieNollie Girona, Catalunya, Northen SpainPosts: 2,712
    I agree with most of Hogweeds recommendations, with the exception that I would lay the sleepers straight on a trench of compacted hardcore/gravel, without the concrete topper. The weight of the sleepers will hold them in place, there is no need to fix them to any sort of solid base as its not very high. Laying the sleepers on a permeable base allows them to ‘breathe’ and dry off after rain. Extending the trench of gravel in front a bit would also assist patio drainage, although your patio should have a drain installed with a slight fall towards that drain.

    If you create a long bed along the top level, either side of the steps and plant that up with a line of shrubs or make it a mixed border, like AlliumPurpleSensation’s, that should absorb excess water as well as frame the two levels nicely.
  • ObelixxObelixx Vendée, Western FrancePosts: 18,782
    edited 1 February
    Sorry but we no longer live in that house and garden so no recent photos.  Here are a few of the veggie plot and its sleeper walls.
     

    And 10 years later when we'd had to replace the blue planks with roofing beams and erect a wind/chemical spray break.  As you can see, the sleepers are fine and have had no treatment.


    The sleepers were laid on a gravel/broken brick and stone layer for drainage and to level them.  The vertical ones that line the path sloping up to the flattened level were trimmed level after "planting.  The archway was built to support clematis and thus hide my work/potting area between the house and sleeper wall.
    "We don't stop playing because we grow old; we grow old because we stop playing." - George Bernard Shaw
  • WaysideWayside Posts: 729
    edited 2 February
    On end sleepers have the benefit of letting drainage through between them.  But this is a lot of work and a lot of expense.

    Our garden is about 30ft high, so trying to level off and master the slope is a must!

    You could re-landscape into two levels and use a slope in-between that you plant out.  Then it will be hidden and your only expense will be the steps.  You can make steps using cut/sleepers and hold back with re-bar.

    If you haven't space then I understand more-so the need. 

    Be aware that if you use softwood sleepers you must drain them.  Old school ones are covered with so many chemicals they hardly ever rot!

    I've a neighbour that got going with sleepers on their garden, and it spread to the entire thing.  And the start began to rot before he finished at the end.

    If you have a relatively low wall consider dry stone walling, it will drain naturally.

    And depending on length, you could do a couple of low walls rather than one high.


  • KeenOnGreenKeenOnGreen Posts: 517
    Be aware that, even if treated, sleepers can rot relatively quickly under certain circumstances.  Use membrane between the sleepers and any gravel/soil (avoid non-breathable plastic/tarpaulin).  Avoid any soil touching the sleepers. Do not let any plants grow over the tops of the sleepers, as in our experience mould quickly developed on the sleepers and they are now rotting quickly.  

    Put a deep layer of gravel behind the sleepers (see the photo below). The sleepers are under the grey membrane, which was then folded back over the gravel.


    This is it after it had been finished, and before planting.



    We then planted on top of the gravel (with Opheopogon grass).  Big mistake, it created humidity and shade on the top of the sleepers, which started to rot them.  Try to keep the area immediately behind the sleepers clear, and with good air flow.

    Let me know if you have any questions.  
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