Water table entering sub floor.

Discussion in 'Builders' Talk' started by GussMan, Feb 12, 2019.

  1. GussMan

    GussMan New Member

    Hey there,

    On a job, and the client has water coming through up a thin concrete slab foundation (2inch) near wall. The rest of the concrete slab is about 15cm thick and is dry.

    Don't think we need to have DCP'ing, just think we need to build up the thickness of the concrete slab foundation where it is thinnest. and add more ventilation.

    The property is built on clay and is mid 1930's.

    What do you think is the best course of action?
     

    Attached Files:

  2. KIAB

    KIAB Super Member

    Have you ruled out any old leaking pipes.
     
  3. GussMan

    GussMan New Member

    Hey Kiab,

    Yea, we kept an eye on it over a month and it came and went, dried up and then re-filed etc. In the dry period all, the pipes were working in the house. All external pipes are sound as well. The whole house had been re plumber internally as well. The water only seems to get up to about an inch and a half above ground.

    Cheers
    G
     
  4. KIAB

    KIAB Super Member

    Could look at improving drainage outside that window,what about digging trench lay land drainage pipe covered with clean gravel to collect water & pipe away from area.
     
  5. GussMan

    GussMan New Member

    Thanks. We have an Aco drain already around the property. So think its the water table pushing up. The latest ingress occurred after a large snowfall.

    That's why I was thinking of bringing the concrete level up to a similar level to the 15cm slab. Maybe adding a waterproof plastic layer beneath that.

    Thnaks
    G
     
  6. GussMan

    GussMan New Member

    Or just ballast and then concrete.
     
  7. KIAB

    KIAB Super Member

    What type of Aco drain
     
  8. GussMan

    GussMan New Member

    Black plastic inlayed to concrete
     

    Attached Files:

  9. KIAB

    KIAB Super Member

    Well that will only collect the surface water, not what's below ground, that why I suggested land drainage to collect & take water away from property.
     
  10. GussMan

    GussMan New Member

    Yea, appreciate that, just thinking if it's water table it might be forming underneath the house as opposed to down the side and then under?
     
  11. sospan

    sospan Screwfix Select

    Quite a few options and combinations of them together; reduce the outside levels, increase the height of the slab under the floor, tanking, fitting in a sump and pump.

    Don't know whether it is the camera angle - are those floor joists undersized ?
     
  12. KIAB

    KIAB Super Member

    Looks more like 4x2's.:eek:
     
  13. chippie244

    chippie244 Super Member

    Or run away.
     
  14. GussMan

    GussMan New Member

    Yea 2X4's, some lovely old beams. Going to get some sister joists to help out with that. :0)
     

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