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Retrofitting weep holes on retaining wall

chris5fdxqUAVchris5fdxqUAV Posts: 6
in Problem solving
Hi all . I had a brick retaining wall done “professionally” which they have not put any sort of weep hole or drainage . It does get particularly wet behind the wall . 

So I’m looking at retro fitting some sort of weep hole system . I know I could drill holes at certain intervals along the wall and insert some sort of pipe or weephole but I’m also wondering if I should dig a trench behind the wall and fill it with gravel or something .

Posts

  • JennyJJennyJ Posts: 10,576
    How long ago did you have the wall built? If it's not too long,it might be worth going back to the people who did it, explaining the problem (that the wall is retaining water as well as soil) and seeing what they suggest. It might not have been designed for the weight of water as well as soil.
    Doncaster, South Yorkshire. Soil type: sandy, well-drained
  • Chris-P-BaconChris-P-Bacon Posts: 943
    chris5fdxqUAV said:
    Hi all . I had a brick retaining wall done “professionally” which they have not put any sort of weep hole or drainage . It does get particularly wet behind the wall . 

    So I’m looking at retro fitting some sort of weep hole system . I know I could drill holes at certain intervals along the wall and insert some sort of pipe or weephole but I’m also wondering if I should dig a trench behind the wall and fill it with gravel or something .
    Yes, do all of those things. Fill with gravel - 10 to 20mm should do... with a perforated pipe obviously. The diameter of the pipe will be dependant on the size of the job but I think something like 15mm -25mm HDPE would be ok. In all likelihood it will remain wet but relieve pressure.
  • chris5fdxqUAVchris5fdxqUAV Posts: 6
    I’ve seen where they run a pipe along the length of the wall . Where do I need to run this into ? As am I only transferring the water from one place to another ?
  • Chris-P-BaconChris-P-Bacon Posts: 943
    Some photos would be helpful.
  • Dave HumbyDave Humby Posts: 1,145
    Has the wall been backfilled yet? How high is it? What is the construction?
  • chris5fdxqUAVchris5fdxqUAV Posts: 6
    It’s a wall that’s 5 courses high and about 30cm deep 
  • chris5fdxqUAVchris5fdxqUAV Posts: 6
    Traditional brick construction 
  • wild edgeswild edges Posts: 10,497
    Normally drainage is only required for a retaining wall if it's holding back over 1200mm of water-retaining soil. The purpose is to reduce the pressure of water on the back of the wall rather than to keep the soil dry though. A good builder should consider some way to reduce the risk of ponding though. The land drain would only really be needed if you have a lot of water building up or if you're worried that weepholes would cause staining or flooding at the lower level. If you're happy that water is ok to flow through without causing any harm then drilling a few weepholes would be the first step, if that proves insufficient then you can consider upgrading the drainage further.
    If you can keep your head, while those around you are losing theirs, you may not have grasped the seriousness of the situation.
  • chris5fdxqUAVchris5fdxqUAV Posts: 6
    It does seem if the lawn begins it gets very wet . The garden slopes towards the wall . I’d prefer not to have weep holes as they may stain the wall and patio . I don’t mind digging behind the wall then adding some gravel etc . I’d also thought about planting behind that wall a bed of something .
  • chris5fdxqUAVchris5fdxqUAV Posts: 6

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