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Advice on what to do with existing turf bed before laying new ornamental turf

I inherited a very tired, weedy lawn that I want to re-shape, level, and re-lay; it is approx 7m x 8m.  The idea is to create a striped carpet of ornamental turf, having done something similar before to some success, over a fairly heavy soil bed approx 9-12" above London sub-soil.

The inherited ground has been laid as follows (going from deepest up to surface): good, thick soil - a black, material membrane - a layer of black "soil"/grit with lots of small stones - some vivid red "soil" with larger stones (say 1" square) - between an 1" and 4" of topsoil, which the turf sat on.

I should have treated the existing turf with weedkiller first, as it did have quite a few dandelions which will no doubt show their hand again!  I didn't as I thought I was going to dig the lower layers over and pick out the debris, however now I'm not sure.


However my current approach is likely to be, working across the ground in areas/batches:

  1. skim off the remaining top soil
  2. remove the membrane, by either temporarily moving the two intermediate layers then pulling up the membrane, OR by excavating a small channel every 2 ft, cutting the membrane and pulling out sideways/up (if poss)
  3. putting the two layers back onto the good base soil and digging before levelling
  4. adding existing + new top soil back and levelling again

Alternatively I could leave the top soil in place, try to pull up the membrane in 2ft strips, then level and add sufficient new top soil to create final level.


I don't think I'll have enough extra depth to just add new top soil, and I think the resulting level wouldn't be deep enough for the grass, nor the membrane give enough drainage/root run, to be ultimately good enough long-term.


What are people's thoughts? 

Also, does anyone know of a better way of getting membrane out without super human strength/effort?


  • Dave MorganDave Morgan Posts: 3,123

    Old laid membrane is a pain to remove, it tears. If I understand properly what you've outlined you'll be laying on top of an existing lawn. Are you laying synthetic turf or the real thing?

  • Real, ornamental, Dave - and thanks for replying.

    Apologies for the lack of clarity - during composition of the OP, I removed my mention to the fact I've already used a turf cutter to remove the turf.  Therefore I am, to a lesser extent, laying on an existing bed/soil and topping up to required level with new top soil.

  • Dave MorganDave Morgan Posts: 3,123

    Well if it's a permeable membrane, there's no real need to remove it. That is as long as you have sufficient depth of soil above it. It's just a case of laying a new lawn. As you've done it before you know how. It won't settle much due to the membrane.

  • I don't believe I have sufficient depth - what shd I therefore do?
  • Dave MorganDave Morgan Posts: 3,123

    Grass needs just a few inches 4 max to set down roots properly. Many lawns are laid on a lot less on new build property.

    Permeable membranes allow nutrients and micro biology to move back and forth, and drainage won't be a problem.

    So that's the depth your'e aiming for to lay on.

    If you haven't got that much then it'll be difficult for the new turf to take.


  • I thought it was preferable to have dug to, or a root run of, a spade's depth, thanks for your clarification Dave.

    I'll be doing a wood lawn frame with the level today or tomorrow so I'll know how much top soil depth I have.

    Does anyone have any other comments or advice?
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