Hire the best Landscaper

Top layer of backfill for retaining wall

Results 1 to 5 of 5
  1. #1
    Novice
    Join Date
    Jul 2010
    Location
    Central Vic
    Posts
    31

    Default Top layer of backfill for retaining wall

    I have some questions about what do use for the top layer(s) of backfill for a retaining wall.

    The Timber QLD data sheet says stick 100mm topsoil on top of the free-draining fill and grow grass on it.

    Grass is what we want, but I want to know

    1) will there be a problem with the topsoil percolating down into the scoria backfill? If so, how can I avoid that? I have plenty of clay available but I guess that may be worse. A layer of finer agg or crushed rock with fines first? Or a layer of geofabric on top of the scoria?

    2) Is 100 mm of topsoil before hitting scoria really enough to avoid rocks poking through etc? Should I at least do 100 mm of clay + 100 mm of topsoil?

  2. #2
    Registered User
    Join Date
    Nov 2007
    Location
    Orstralia
    Posts
    259

    Default

    Clay is no good as it defeats the purpose of the scoria.
    You can buy Geo Fabric that is fine enough to stop the small particles.
    Once established the grass will do the same thing.

  3. #3
    Novice
    Join Date
    Jul 2010
    Location
    Central Vic
    Posts
    31

    Default

    Ta so you reckon a layer of geofabric and then 100 mm of topsoil? Will that be deep enough for the grass roots or should I go 200 mm?

  4. #4
    1K Club Member
    Join Date
    Nov 2008
    Location
    Sydney
    Posts
    1,108

    Default

    Yep geo fabric, would have 200 mm min soil for turf or it will dry out to rapidly during summer.

  5. #5
    Novice
    Join Date
    Jul 2010
    Location
    Central Vic
    Posts
    31

    Default

    Thanks for that. Maybe I should put a thin layer of sand or 1/4 minus on top of the geofabric to stop the topsoil clogging it?

    Or am I over-thinking this?? (As usual!)

Similar Threads

  1. No fines concrete backfill
    By NickH in forum Retaining Walls
    Replies: 4
    Last Post: 20th May 2010, 12:01 PM
  2. Good Wall Backfill and Drainage contractors?
    By RedRaven in forum Retaining Walls
    Replies: 0
    Last Post: 17th Aug 2009, 06:35 PM
  3. New Layer
    By LegacyGT in forum Landscaping, Gardening & Outdoors
    Replies: 0
    Last Post: 6th Jul 2008, 11:09 AM
  4. Replies: 3
    Last Post: 3rd Nov 2007, 05:06 PM
  5. Footings in backfill
    By gsouth in forum Sub Flooring
    Replies: 10
    Last Post: 10th Jan 2006, 05:55 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •