1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

Cavity walls construction

Discussion in 'Building Regulations and Planning Permission' started by ant3000, 7 May 2020.

  1. ant3000

    ant3000

    Joined:
    7 May 2020
    Messages:
    4
    Thanks Received:
    0
    Country:
    United Kingdom
    I’m looking for a little advice re; the construction of mine and my neighbours terrace of houses. In the last year or so we’ve started to suspect that rats have accessed our cavity walls and are moving between the properties.

    We have each noticed burrow holes coming out from close to the external walls and so have dug down a little and now believe that the foundations may be suspended block and beam meaning there is a cavity running underneath all of the properties in which the rats have started to nest (possibly gaining access via damaged drainage).

    Where we have dug we have discovered that drainage lintels run at sections along most of the front wall and can see the cavity runs right under the houses. We’ve been able to photograph up into the cavity wall and this appears to be completely open at the bottom and we can see the air brick housing and damp course. Is this considered to be ok? Should a “cavity tray’ been fitted above any exposed areas of the cavity wall?

    It just seems to be an open door to pests?

    Any advice would be much appreciated.
     

    Attached Files:

  2. Sponsored Links
  3. noseall

    noseall

    Joined:
    2 Feb 2006
    Messages:
    43,499
    Thanks Received:
    2,688
    Location:
    Staffordshire
    Country:
    United Kingdom
    There appears to be a lintel (over a drain etc) in the image. Its a difficult one to manage in terms of building rules and reg's. There needs to be a clearance above and around the lintel to protect the drain with little regard for vermin access.
    You need to dig around and below the lintel to fully expose the bridged gap and look how to block up the hole without compromising the pipe beneath.
     
    • Like Like x 1
  4. ant3000

    ant3000

    Joined:
    7 May 2020
    Messages:
    4
    Thanks Received:
    0
    Country:
    United Kingdom
    Should a cavity tray have been fitted above the drainage access but below the damp proof course?

    My concern is that the cavity wall hasn’t been filled below the DCP throughout the walls? Is this conceivable?
     
  5. noseall

    noseall

    Joined:
    2 Feb 2006
    Messages:
    43,499
    Thanks Received:
    2,688
    Location:
    Staffordshire
    Country:
    United Kingdom
    Possibly, or some kind of shuttering or packed with insulation.

    Strange that none of it is filled, very odd. It does get tricky trying to maintain clearance around passing sewer pipes whilst attempting to fill the cavities above them, but this should not affect the rest of the build in terms of filling.
     
    • Like Like x 1
  6. Sponsored Links
  7. ant3000

    ant3000

    Joined:
    7 May 2020
    Messages:
    4
    Thanks Received:
    0
    Country:
    United Kingdom
    I’ll have a dig past the drainage opening and see if I can get another pic
     
  8. ^woody^

    ^woody^

    Joined:
    3 Sep 2006
    Messages:
    34,017
    Thanks Received:
    4,618
    Location:
    West Mids
    Country:
    United Kingdom
     
    • Thanks Thanks x 1
  9. ant3000

    ant3000

    Joined:
    7 May 2020
    Messages:
    4
    Thanks Received:
    0
    Country:
    United Kingdom
    It seems that might be the case which is why I figured they should have blocked access below the dpc
     
  10. ^woody^

    ^woody^

    Joined:
    3 Sep 2006
    Messages:
    34,017
    Thanks Received:
    4,618
    Location:
    West Mids
    Country:
    United Kingdom
    It's difficult to see what's going on there, but in general terms, cavities should be filled up to around 225mm below ground level. When pipes are close to this level it can be awkward as pipes require some space around them in case the building moves, so yes there are times when the cavity is just left open above and around the pipe.

    If that's a route in, then you need to block the cavities with some stainless steel mesh scrumpled up to wedge in, and form a barrier. You can also afford to infill with some lean concrete to close up any large voids, and put the mesh around the pipe in a 50mm or so perimeter
     
    • Thanks Thanks x 1
  11. DIYnot Local

    DIYnot Local

    Joined:
    3 Sep 2019
    Country:
    United Kingdom

    If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

    Select the supplier or trade you require, enter your location to begin your search.


    Are you a trade or supplier? You can create your listing free at DIYnot Local

     
Loading...

Share This Page