Loose paving on steps

Discussion in 'Landscaping and Outdoors' started by mikehatt86, Jun 4, 2020.

  1. DIYDave.

    DIYDave. Screwfix Select

    Most patios and paths would also be edged by some form or another which helps support and prevent slabs/blocks from moving and not creeping over time

    This could be the walls of the house, fence gravel boards, brick edging or cement haunching, etc

    These steps are free standing, nothing around the edges to help lessen movement

    Take a look at The Paving Expert Site

    Well recommended and agreed as a source of good advice and excellent point of reference

    Various methods of step construction and using different materials shown (search Steps under index) but building steps with slabs / pavers / similar shows a poured concrete pad taking up the void - can be hardcore under this to firm ground if needed and to bulk out void, but not mortar directly onto loose fill

    Then full mortar bed under slab

    Yes other sites may well show this construction method, laying slabs over mot/sub base of course, that’s an option and there’s loads more - strip foundations, brick and blocks laid, etc

    But how deep is the mortar bed going to be under the slabs - 15/20/40mm

    Thicker the mortar bed, more weight and gravity will keep it in place - as long as adhered to slab in the first place

    But unless sub base is super compacted, the slab and mortar attached could be lifted up as it’s not going to fully bond to the full depth of sub base - only the top layer

    Not like a shed base or slab where your pouring 75-100mm concrete over MOT/ Sub Base, where sheer weight alone will keep it in place - wether or not it’s bonded itself to the base

    I would imagine the remaining mortar is going to lift easily from the sub base with bits of stone stuck into it - looking like peanut brittle

    Hopefully better adhered to brick, but again, only 100mm edge on bottom step, 2x100mm on top step

    Good luck whatever method you go with
     
  2. Russell James

    Russell James New Member

    Hi, you will not get great adhesion with sharp sand. 6:1 is far too weak. Use building sand and you can go as strong as 3: 1 if you like, needs to be quite wet like brickies muck. This product that you paint on the back of the slab sounds like it would work, although I've never used it.
     
  3. mikehatt86

    mikehatt86 New Member

    Thanks for the comments and advice everyone.

    Just to clarify, the infill used for the centre of the steps was MOT which I compacted down, then a fine layer of ballast on top just to get it flatter, which I also compacted. In hindsight I should have done a brick back row for the bottom step!

    As for the mortar i'd read in a few places online that I should be using 6:1 sharp sand/Cement, but it sounds like that isn't agreed by everyone. I did thoroughly wet the bricks and slabs prior to putting the mortar bed down. The mortar has actually adhered very well to the bricks and the infill, not shifting at all. It was just the slab which it hadn't stuck to.

    So after doing a bit more research online I found that some people have had success with doing a thin layer of SBR/Cement in similar situations to mine. I decided to give this a try before taking up the full mortar bed. I made a slurry, getting a good paste like consistency then brushed this onto the solid mortar bed and onto the back of the pavers then put them back in position.
    Did this Friday morning and its absolutely rock solid, slabs not moving at all. Time will tell whether it's a permanent solution but thought it was worth a try.

    Paving for the patio cut and dry laid, ready to fix down tomorrow.

    Patio 3.jpg
     

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