Amendments in Building regs plans due to a Water Well discov

Discussion in 'Building Regulations and Planning Permission' started by SALL2009, 20 Mar 2012.

  1. SALL2009

    Joined:
    15 May 2009
    Messages:
    630
    Thanks Received:
    2
    Location:
    West Midlands
    Country:
    United Kingdom
    Basically as we were digging the foundations builders have found a well on the edge of the trench. Building regs inspector has asked for updated plans sent to them to be approved. The plan needs to incorporate what we plan on doing to avoid disturbing the well.
    The suggestions he has given are, either filling it in or using lintels. I am seeing my architect tomorrow and I will get the plans updated and sent for re-approval. I was just wondering if anyone here has come across a situation where you had to avoid putting any load on a well or anything similarly sensitive.

    The well is towards the end (of the side wall/trench) of the new extension. It has been suggested that we extend the trench a further 2 feet or so and run a lintel from there to avoid any load being on the well (or location close to it).
    Would there be a recommended clearance required from the well.
    Is there a recommended span of the lintel for such a situation?

    Any possible suggestions of options would be very helpful. I don’t think filling is an option as the well is quite big.
     
  2. ^woody^

    Joined:
    3 Sep 2006
    Messages:
    14,012
    Thanks Received:
    1,435
    Location:
    Birmingham
    Country:
    United Kingdom
    Yes you either fill it or bridge it

    But in bridging it, you still need to be sure that loads are dealt with, and will not cause the well to collapse inwards further down

    It may be an engineer that you need rather than an architect, if building control are not happy with any suggestions or guesses
     
  3. SALL2009

    Joined:
    15 May 2009
    Messages:
    630
    Thanks Received:
    2
    Location:
    West Midlands
    Country:
    United Kingdom
    Spoke to the architect today and it seems bridging might not be an option as 45 degree foundation rule would mean that the pad stones would need to be close to the depth of the well (Which is DEEP).

    So I am now looking at pile foundations or filling the well in.

    Can someone help me with calculation of how much hardcore would be needed to fill the well in?

    The diameter of the well is roughly 2 meters and 6 meters deep.

    According to my calcs this comes out to be 19 cubic meters.

    If this is correct, can any one tell me how many tonnes of hardcore would be needed to fill 19 cubic meters?
     
  4. ^woody^

    Joined:
    3 Sep 2006
    Messages:
    14,012
    Thanks Received:
    1,435
    Location:
    Birmingham
    Country:
    United Kingdom
    Confirm with your BCO or engineer if H/c is acceptable - it will compact over time, and can't normally just be tipped in. It may be a case of filling and bridging

    A tonne is about 0.8m3, but you need to allow for compaction too, so perhaps someone else can work that out
     
  5. Nige F

    Joined:
    28 Jun 2005
    Messages:
    16,845
    Thanks Received:
    937
    Country:
    United Kingdom
    Pi x R.squared x H ;)
     
  6. SALL2009

    Joined:
    15 May 2009
    Messages:
    630
    Thanks Received:
    2
    Location:
    West Midlands
    Country:
    United Kingdom
    Woody, You said filling and then maybe bridging also. But the pad stones of the bridge wouldn't need to be at the original depth of the well right? Otherwise, what would be the point in filling it in?

    I am also looking at getting pile foundations.
     
  7. Static

    Joined:
    20 Dec 2005
    Messages:
    2,026
    Thanks Received:
    168
    Location:
    East Sussex
    Country:
    United Kingdom
    RRRiiightt.. What about capping the well? May be time to take the calculator off the architect and give it to someone else.. as suggested above
     
  8. SALL2009

    Joined:
    15 May 2009
    Messages:
    630
    Thanks Received:
    2
    Location:
    West Midlands
    Country:
    United Kingdom
    The well is already capped on top (with a brick cap and then few feet of soil to ground level). We only found out about its existence once we started digging. We have lived here 15 years and the ground has never shown any signs of sinking.
    But as the well is still intact below the cap, building control inspector said that the pad stones of the bridge need to comply with 45 degree foundation rule.

    Could a structural engineer come up with another solution?

    The whole project is 7 feet by 10 feet and single story.
     
  9. Static

    Joined:
    20 Dec 2005
    Messages:
    2,026
    Thanks Received:
    168
    Location:
    East Sussex
    Country:
    United Kingdom
    Yes, building control are more than happy when an SE takes liability for design.. but would have thought a reinforced concrete cap on top would be a possible economic solution..
     
  10. SALL2009

    Joined:
    15 May 2009
    Messages:
    630
    Thanks Received:
    2
    Location:
    West Midlands
    Country:
    United Kingdom
    Thanks. Will speak to a SE and see what he says.
     
  11. inspectornumberone

    Joined:
    27 Mar 2012
    Messages:
    5
    Thanks Received:
    0
    Location:
    West Midlands
    Country:
    United Kingdom
    easiest is to fill it with lean mix. no compaction needed. i bet you would love to go down the 6m and start compacting the hardcore in 150mm layers! £1.9k to the ready mix company would be cheaper than piles! engineer could design a heavy raft also. what did your engineer say anyway?
     
  12. sjt73

    Joined:
    17 Apr 2012
    Messages:
    1
    Thanks Received:
    0
    Location:
    Northamptonshire
    Country:
    United Kingdom
    The Environment Agency has guidelines for decommisioning old wells. You should ask for their advice first. If you contaminate the water table, you'll be up a creak.

    You may also be required to inform the British Geological Survey once you've done it.

    I worked with boreholes and wells for 12 years as part of my job. The last Victorian well I had filled in took about 40 tonne of aggregate. Good luck.
     

Share This Page