Exterior Drainage

Discussion in 'Plumbers' Talk' started by Mark2260, Aug 23, 2019.

  1. Mark2260

    Mark2260 New Member

    Hi Everyone,
    Hopefully I can get some advice please, my wife and I bought a bungalow last xmas and we have been slowly working through the jobs on it, we have so far had a re wire and new heating, new bathroom and windows and doors, we are thinking this could be our last move and the house although old and needs modernizing is very nice.
    Anyway we have had a wet floor void in the old kitchen which is now a dining area, we traced it to dodgy drainage at the side of the house and did a temp repair but the ground stayed damp as did the outside foundation walls fast forward to last weekend, the drain on the extension backed up so we got a jetter in and a lot of dirt came down the waste line into the manhole and out the other side, i forgot to mention all the drains go into a main drain including the soil pipe as its a 60`s build bungalow, a camera was put down and showed a collapsed pipe, so we assume all the rain water and sink waste has been going into the ground for a few months before it fully collapsed.
    Now my question is as the sewer pipe is fine into the manhole, instead of digging all the old drains out at about 12m in length and a meter down can i close the old drains off and install new plastic drains and just run them into the manhole?. I've attached a drawing and hopefully it is clear to understand, the new drains would be about 400mm below ground I believe and would only carry rain water and shower and sink water.
    The soil vent stack was a soil pipe to a loft conversion upstairs that was removed, the other bungalows that have the toilet running under the bathroom floor like ours dont have a vent stack, the drainage pipe work is just over a meter from side of house. Blue is old clay pipe and magenta would be new plastic on the section drawing.
    I would appreciate any advice please.
    Many Thanks
    Mark Capture.JPG
     
  2. Mark2260

    Mark2260 New Member

  3. Mark2260

    Mark2260 New Member

    Updated
     

    Attached Files:

  4. Tony Goddard

    Tony Goddard Screwfix Select

    Why not just dig up and replace the damaged section of the pipework?
     
  5. ecoplumbing

    ecoplumbing Active Member

    Looking at the new plans, it doesn't really look a good design joining into the manhole. If the new drainage simply drops into the existing manhole without being properly channelled, it will block. Please correct me if I'm wrong but that's how the drawings appear.
    If the condition of the downstream drainage from the existing mh is fine then would it not be easier just replacing the damaged section?
     
  6. Mark2260

    Mark2260 New Member

    Hi, I thought of repairing but at the moment it's 2m of collapsed drain and the branch next to it but it would mean digging 7m long 1m deep, it seems easier just to put new in for surface drain and keep soil drain.
    Cap off the old stuff, run the new into access point then use a core cutter to go through the side of the manhole, then drop a section of pipe down in line with main run, I could just repair the rear section but all the gulleys have separated fro. The down sections and some of them are broke at the joint above the old p trap also two of the look to be partially blocked with cement as it won't shift. Really everything from the rear of the manhole wants replacing to be sure. Seems easier to just abandon the old and run new above it
     
  7. Tony Goddard

    Tony Goddard Screwfix Select

    Why run above though, dig out the existing run and put new in
     
    KIAB likes this.
  8. Mark2260

    Mark2260 New Member

     
  9. Mark2260

    Mark2260 New Member

    It's a meter down and about 8-9m long all in, the new stuff goes in about 450mm deep.
     
  10. ecoplumbing

    ecoplumbing Active Member

    Personally I think it'd be better installing a new access chamber with the toilet being the main channel, you can lay the other pipework at a higher level to save work then drop it down into the new chamber. Really wouldn't be that much more work
     
  11. Mark2260

    Mark2260 New Member

    Hi, I did think of that but the chamber there is fine plus the bathroom has just been done and tiled so I don't want to disturb the old clay pipes tgat go down through the floor, I'm going to start digging today at the back as I have a feeling it was a cowbow install there and that pipe is plastic.
    I think it was never put in right and the old clay and plastic has leaked and washed substrate away and caused the collapse, if so I might just have to repair there, the try to replace the old clay p traps with bottle traps as I can see all the joints have opened over the years by about 20mm.
    I will share images as I go along, I'm hopi g I don't find any voids down there..
     
  12. KIAB

    KIAB Super Member

    +1

    Best option,if you replace just odd section of old pipe, you can bet other old sections will need replacing at later date,so do it right, replace the lot.
     
  13. Mark2260

    Mark2260 New Member

     
  14. Mark2260

    Mark2260 New Member

    Hi, that was the idea but new installs of surface drains don't go down a meter, this is why I thought of abandoning the old surface drains and installing new at 500mm depth and running into existing inspection chamber while just keeping the old soil pile going in. It seems pointless to dig up the old when there's no need unless I'm missing something, anyway there's a drainage chap coming out Monday to look at what's best, we will see then, I will let him dig
    I started digging a bit today, all bloody clay.
     
  15. Mark2260

    Mark2260 New Member

     
  16. Mark2260

    Mark2260 New Member

    collapse 3.jpg collapse 4.jpg I've took some images and I'm not sure you could even dig the old drains up as a concrete fence was put up many years ago.
    Red outline is collapsed area.
     
    Last edited: Aug 25, 2019
  17. Mark2260

    Mark2260 New Member

    added images, someone in there wisdom built a fence near enough on top of the old drains 25 years ago according to my neigbour, this is my problem, this is why I didnt wat to risk digging it all up as the fence is concrete and may just start to fall.
    I think when tex arkanses put the new drains into the old the ground settled over the years and the drains opened on the joint and then spent the remainning years washing soil away till it wasnt able to support itself and finally collapsed, only my opinion though.
     
  18. KIAB

    KIAB Super Member

    That fence is probably the cause of all your drain problems.:)
     
    The Teach likes this.
  19. The Teach

    The Teach Screwfix Select

    As already mentioned,repairing (like for like) seems the cheapest option. No building regulation involvement or costs ;)

    or ask a drain company if the damaged section can be relined or something similar.

    replacing the complete underground drain run has its difficulties and only when the ground is opened up, then the route can be planned in conjunction with the drain installer and what the building control person will eventually sign off.

    Drains :D
     
  20. Mark2260

    Mark2260 New Member

    maybe the fence is part of the problem, who knows, i am leaning towards the original plan of all new drains seperate and dropping a single pipe in the chamber from a small access point as in my drawing in magenta not the section view, ive been quoted £500 all in for this approach.
     

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