Bit of builders advice please

Discussion in 'Off-Topic Discussion' started by Loofah, Sep 4, 2021.

  1. Loofah

    Loofah Admin Staff Member

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    This is the old side of the house (build 1927). The wall is single skin with (now) a 50mm dry lining inside.
    The pic shows a drain and the other side of the wall is a fireplace in a room about 8m x 4m. I can't explain why but the floor is about a third floorboard with air under and the rest seems to be solid concrete slab, including the area with the hearth.
    Recently we had heavy rain and it started to smell damp. The hearth became mouldy and i was clear there was a water issue hence the digging!
    It's specific to this location and the water in heavy rain floods off the roof as it flows around the chimney above (which is covered and not letting in water - already checked) and creates a waterfall by completely missing the downpipe.
    You can see the soil is too close to the dampcourse so that's getting reduced but I'm curious about that sealed gully. It's looks to be storing water (absorbing it and storing) but I have no idea why it's even there. Before I smack the concrete lid open, does anyone have any bright ideas on what I might do to remediate?
    I'm currently planning on several things- reduce the soil level, add hardcore around the chimney / flood area and to repoint a few areas where the mortar is failing. Also pondering removing the brick perimeter to the gully as it's built up to the dampcourse.
    But I'm most interested in that weird gully!

    PXL_20210902_145414112.jpg
    PXL_20210904_130313007.jpg
     
  2. pete

    pete Growing a bit of this and a bit of that....

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    Cant really picture it myself, chimney?
    I can see the covered over gully, also an airbrick further along.

    It the soil level at DPC height at the moment?
    If so the airbrick looks to be above DPC, so assuming that is ventilation under the floor.

    Also the gullies appear to be above DPC.
    Is that a soakaway, and if so is it blocked up.
     
  3. shiney

    shiney President, Grumpy Old Men's Club Staff Member

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    I know very little about building so I may just be confusing the matter.

    Is the area below the sealed gully solid or is that soil I can see? It reminds me of what could have been the bottom of a stack pipe for aerating gullies or drains. :dunno:
     
  4. Loofah

    Loofah Admin Staff Member

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    Couple of extra pics if it helps but the main bit is why is there a filled in gully?

    Air bricks are fine and for the area which is a timber floor with air underneath. Yes, as mentioned the soil is to the damp course so too high and going to be reduced.

    Gully is below the dampcourse but the perimeter enclosure is built right up to the dampcourse which is why I thought about removing it.
    Could easily be a soakaway somewhere but haven't seen it backed up yet. Will keep an eye out.

    It's the concrete stack Shiney; the bit the drain sits in. It looks as if there was one, then they filled it in and built another one adjacent. Hadn't thought of an aerating gizmo but there's no vent.

    Think I'm going to smash it open tomorrow :) Am pretty sure its just a big load of water soaking through into the concrete as everything is too close to the dampcourse and the water cascading there in heavy downpours is making it worse.


    PXL_20210904_154024161.jpg PXL_20210904_154017556.jpg
     
  5. Scrungee

    Scrungee Well known for it

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    Kitchens, sculleries, etc. generally used to have solid floors. Perhaps there was a sink inside discharging into a double gully outside, and when the sink was removed part of the gully was sealed.

    Any sign of something like this under the brick upstand?

    [​IMG]
     
  6. Loofah

    Loofah Admin Staff Member

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    Nope! Good thoughts though. I haven't got a pic but the floor is a total shambles, it's like they were using up wood, patching areas and then decided to start with concrete!
     
  7. ricky101

    ricky101 Total Gardener

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    Hard to say what its original purpose was, it could even have been a double downpipe from the original guttering ?
    It could also be an old pipe going through the wall below the top of those surrounding bricks and the water might be going back inside if the pipe was left open ?

    What catches our eye is that the downpipes shoe looks like it could, in downpours, spurt the water over the brick edge rather than into the drain.

    It sounds like the air brick is sitting on the DPC rather than todays way where its above the air brick.
    Once the soil is taken down to at least 6" below the DPC does the rest of the garden allow the excess water to flow away from the wall ?

    Though you say heavy rain can overflow the guttering, it noticeable that there is no real build up of algae on the wall at the bottom, which you would expect to see if the wall was being soaked badly.

    You can get clear products to help seal brickwork above the DPC should that be where its coming in.
    Water Seal | Thompson's Weatherpoofing
     
  8. Loofah

    Loofah Admin Staff Member

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    Thanks Ricky, that's a really good point about algae. I'm going to bust it open tomorrow to see what's happening in there but also have another poke about as far underneath as possible.
    Water runs away and it's quite sandy soil so it drains well come what may but it's getting in somehow
     
  9. JWK

    JWK Gardener Staff Member

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    Maybe there was a sink with the waste going to that second gully.

    The detailing on the chimney is wrong, looks like someone has used tiles instead of lead flashing, it's bound to leak.
     
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    • ricky101

      ricky101 Total Gardener

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      As @JWK says, if its leaking around the chimney it would make sense with you getting mould around the hearth if its running in that way, but you could still have a problem with the drain as well?
       
    • Loofah

      Loofah Admin Staff Member

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      Definitely not coming in through the top of the chimney and can't see any evidence of leakage at the roofline via the loft.
      Would certainly explain it though.
      Have to go out with the kids for a bit but hoping to look into it more this avo
       
    • Loofah

      Loofah Admin Staff Member

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      I haven't removed that concrete plug yet as when I was repointing and poking about I found quite a few little areas that had small holes or pockets in them, mostly hidden from first glance.
      The area in front of the chimney is now dug out with hardcore under the damp course so not going to cause further damp issue; will get to the rest when it's cooler!!
       
    • Scrungee

      Scrungee Well known for it

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      Have you lowered the water seal level yet to check what's down there?

      Sometimes those rainwater 'gullies' aren't gullies with vitrified clay hoppers and are formed of (rendered) brickworkwork sitting on top of a trap. Check for eroded mortar joints that could permit ingress of water through the wall, plus get your arm down and remove any silt inhibiting flow of water through the trap. I use a 2 pint plastic milk bottle with a cut out opposite the handle.
       
      Last edited: Sep 8, 2021
    • Loofah

      Loofah Admin Staff Member

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      Top tip on the milk bottle! The water gully for the exisiting downpipe looks to exactly as it looks, simple gully connected to drain running off somewhere and doesn't appear blocked. I did find one notable hole just next to it and definitely would be contributing to the problem, now sealed plus has air in front.
       
    • Loofah

      Loofah Admin Staff Member

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      I have got to breaking open the gully...
      PXL_20210920_132453662.jpg

      As you can see, there's a runoff heading under the house. Never seen that before but it can't be good as there isn't another end that I've ever seen so presumably any water entering is going into a concrete floor...
      There's also that whopping hole that definitely breaches the DPC and will be filled shortly. My question is how to best address the drain? Cover and let it dry? Fill with concrete? Expanding foam?
       
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