Building up Raised Patio Sub base

Discussion in 'Builders' Talk' started by MattGWS, Mar 13, 2021.

  1. MattGWS

    MattGWS New Member

    At the moment I have a raised decking above the garden run up to a set of bifold doors. I want to remove the deck and replace with a patio. There’s about 300- 400mm needed to build up to finished level before I can lay the stone. What’s the best material to build up the sub base with? Would it be crushed concrete before I get to my MOT type 1 layer?

    many thanks in advance
  2. Mark Brister

    Mark Brister Member

    Type 1 will be fine as long as you compact it in layers of around 150mm with a medium sized wacker plate.
    Recycled crushed concrete would also be a good option below a thinner top coat of type 1 but if the aggregate is too big and your wacker plate isn’t man enough you won’t get a decent compaction so type 1 would be better. If however, you have a supply of crushed concrete it will do the job just make sure you compact it properly. Nothing worse than laying a nice patio that then starts to subside due to poor compaction. Also, recycled crushed concrete is harder to get hold of in small quantities where as type 1 can be bought in bulk bags.
    MattGWS likes this.
  3. MattGWS

    MattGWS New Member

    Thank you. I was thinking crushed concrete based on cost given it’s quite a sizeable area. Local aggregate suppliers can supply this so thought problem best cost option.

    thanks for the response
  4. Mark Brister

    Mark Brister Member

    If it’s a large area and you can get recycled crushed, then that’s the way to go but just be sure to compact it well. By using crushed concrete you will only need a thin layer of type 1 on top just to level it up, 50-75mm will do the job.
  5. MattGWS

    MattGWS New Member

    Thanks, appreciate the help. Planning to have a wacker plate on site for the week so I can compact each layer as we go
  6. stevie22

    stevie22 Screwfix Select

    Decent crushed concrete won't need type 1. In fact you can buy crushed concrete to type 1 spec if you like (it's only a grading criteraion).

    I have used in in industry and it behaved far better that "proper" crushed limestone and was cheaper by a considerable margin.

    Compaction is the key.
    ramseyman and MattGWS like this.
  7. MattGWS

    MattGWS New Member

    Great, thanks, I’ll speak to the aggregate people about that

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