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New lawn over hardcore

Discussion in 'Lawns' started by ivanol, Apr 15, 2018.

  1. ivanol

    ivanol Apprentice Gardener

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    We’ve just had a concrete slab taken up from our garden with a plan to replace part of it with paving and part with a new lawn sown from seed. The contractors have lifted the concrete, and laid a 10cm deep layer of crushed concrete hardcore as part of the base structure for the paving, but have laid this over the entire area rather than just the part we want paved. Our plan had been to prepare the ground for the lawn by bringing in 15cm of top soil, but with the crushed concrete hardcore there is only space for about 8cm of soil if we keep the level as we want.

    The contractors are telling us that this will be fine, that the hardcore will act as a good base layer for the lawn stop the soil settling too much, and that should drain without any problems. From what I’ve read I have some serious doubts, but am not an expert and thought I’d ask for your thoughts. How bad is the lawn likely to be in only 8cm of soil. I’ve seen lots of write ups about irregular coloured lumpy patches where rubble has been buried under a lawn, but we do at least have a uniform surface. Will it just be a bit drought intolerant, or is it likely to be a real issue? Is the problem fixable by adding a few more cm of soil (we can probably get to 10, but not 15), or is the only option to have all the hardcore dug out?

    Thanks for your advice.
     
  2. Matt-tropical

    Matt-tropical Gardener

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    We had a small path about 6 feet long at the top of the garden I broke it all up into small pieces but left it in place. This was only a temporary fix at the time so I put about 10cm of soil over it followed by the turf. Now most of the time you would never know it was there but when we get a dry spell it’s the first bit to loose it’s green colour. If I was you I would remove it from the area or at least some of it so you can get more soil down. If you could dig it in before you put soil on top it would be the best of both worlds.
     
  3. Tetters

    Tetters Total Gardener

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    Welcome to the forum @ivanol :) You will need to remove the crushed concrete before thinking about lawn. I suggest you tell the contractors to do it as they have not done as you asked, and are trying to fob you off.
    I have a 'hard standing' area here on my site using crushed concrete. When it`s very wet there is a green haze over it, but otherwise it looks awful. :sad:
     
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    • kazzawazza

      kazzawazza Total Gardener

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      I’d also get them back in as they haven’t done what you’ve asked. :wallbanging:
       
    • Scrungee

      Scrungee Well known for it

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      Come the first drought and the grass above the hardcore will die.
       
    • ivanol

      ivanol Apprentice Gardener

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      Thank you everyone. This is pretty much what I thought, but good to have confirmation from you all. Will get the stuff taken out.
       
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