Forum home› Problem solving
This Forum will close on Wednesday 27 March, 2024. Please refer to the announcement on the Discussions page for further detail.

New Build Garden - No Subsoil Help

_Silvio__Silvio_ Posts: 14
edited January 2021 in Problem solving
Hi all, 1st-time post, so looking for some guidance.

Recent new build property and just started to sort out the beds around the perimeter of the garden. As I am suffering from severe waterlogged ground, a french drain needed). I was shocked to discover that below the 10cm of clay topsoil, I have over a meter (not sure how far down it goes) of builders / sharp sand. So no subsoil, meaning I am unable to start amending the soil or plant any fruit trees or shrubs till I can get this sorted out.

I think I will have to hire a mini digger to dig out the sand and replace it with more soil and mix some of my clay and additional compost into the sand. 

What I don't know is how far down I need to go? Can I get away with only amending/replacing 50cm down or do I need to go all the way down to 1 meter?



«13

Posts

  • DovefromaboveDovefromabove Posts: 88,147
    Why have you dug the hole so close to a building?


    Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.





  • _Silvio__Silvio_ Posts: 14
    This is the 2nd hole along that side, I am checking how far the sand is going along this wall, the border will only be about 60cm out from the wall. 

    I will have to dig up the whole border to replace the sand, but not sure how far down to go. This picture was taken to assess how deep the sand gos.

    The wall you see is the next-doors garage.
  • rachelQrtJHBjbrachelQrtJHBjb Posts: 819
    Actually @Dovefromabove, I'm wondering where the foundations are given the proximity of the hole to the wall.

    @silvioTo0IW5eM how high is that wall? I'm thinking of our neighbours who have just had a 1.8m perimeter wall constructed and the footing is probably 80-100cm wide. 
  • Allotment BoyAllotment Boy Posts: 6,774
    I think you need to check other areas away from buildings or walls as this could just be localized overburden , there may be more normal conditions in other spots.  This may save you spending a fortune on importing soil.  
    AB Still learning

  • NollieNollie Posts: 7,529
    It’s worth digging a few test holes further out in case it’s just backfilled with sand around the foundations and there is better depth of soil elsewhere. That’s bad enough, but what’s more worrying is that I can’t see a damp-proof course in the brickwork, you can already see damp seeping into the wall and your mortar is going green. I would get a surveyor to look at that pronto.
    Mountainous Northern Catalunya, Spain. Hot summers, cold winters.
  • _Silvio__Silvio_ Posts: 14
    I would expect the foundations are in line with the wall, but as it's not my garage I am not that concerned on their behalf :wink: but I will have to be careful not to disturb the ground too much if I have to go deep. I will prob have to make the border wider so give myself more working room away from their foundations.

    Any advice as to how far I should be going as don't want my plants to suffer if I haven't improved the subsoil deep enough
  • DovefromaboveDovefromabove Posts: 88,147
    rachelQrtJHBjb said:
    Actually @Dovefromabove, I'm wondering where the foundations are given the proximity of the hole to the wall.

    @silvioTo0IW5eM how high is that wall? I'm thinking of our neighbours who have just had a 1.8m perimeter wall constructed and the footing is probably 80-100cm wide. 
    Just what I was wondering ... 🤔 

    Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.





  • _Silvio__Silvio_ Posts: 14
    pansyface said:
    I don’t know your part of the world at all, but is there a place near you called Sandiway?  Sherlock and I have a feeling that there is a big clue in the name.

    Take a look at this and see if it makes you think.. 

    http://nepubprod.appspot.com/file/6209182138105856


    This is local but not in my area, this site used to be a farmers field which is ironic and surprising to find sand. This is due to the builders making the land up as they call it.
  • NollieNollie Posts: 7,529
    Ok, not your house wall, neighbour’s garage. Still, doesn’t look good in terms of construction quality which would concern me in terms of the quality of your own building. What’s the wooden batten for? If it’s not your wall, bear in mind you can’t raise the soil level against it or attach supports for climbers against it. 
    Mountainous Northern Catalunya, Spain. Hot summers, cold winters.
  • _Silvio__Silvio_ Posts: 14
    edited January 2021
    Nollie said:
    It’s worth digging a few test holes further out in case it’s just backfilled with sand around the foundations and there is better depth of soil elsewhere. That’s bad enough, but what’s more worrying is that I can’t see a damp-proof course in the brickwork, you can already see damp seeping into the wall and your mortar is going green. I would get a surveyor to look at that pronto.
    To the left of the post is the garage, (you can see where the damp proof couse is 2 bricks up) 

    To the right of the post is just a retaining wall as there garden level is 1 meter higher than my garden, this is why this wall is more damp. 

    I do think that retaining walls with soil behind should not be allowing mosture to penatrate as it will affect its long term stabability, but I am no expert.

    I will dig mote holes to see how far the sand gos along that wall, as I know the bottom edge of the garden is just clay subsoil.
Sign In or Register to comment.