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Putting down a patio. Advice needed.

Discussion in 'In the Garden' started by bigpepespunch, 26 Jun 2018.

  1. bigpepespunch

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    Hi Guys
    Long time lurker, first time poster here so bare with me please :)

    I am recently purchased my first house with my girlfriend and the previous owners have left quite a lot of work, which is sort of fun to put our own stamp on it.

    Anyway the first piece of advice im after is regarding laying a patio. When we got the house in the back garden there was some incredibly poorly laid decking which was actually laid above the DPC.

    I immediately took it up as we wanted a patio down. The ground (shropshire) was really full of clay so i dug down 12 inches and used a combination of wickes MOT hardcore and broken up slabs (see pics).

    I am in no way experienced at this sort of thing and am going to wacker it down and cover with sand and then lay slabs. Am i doing it ok so far in your opinions? does the hardcore need to be smaller?

    Any advice and or tips would be amazing. Thanks in advance
     

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  2. scbk

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    Ideally you would've put the rubble down first and then the hardcore/scalpings on top to fill the voids. If you put sand on top of the rubble half of it will disappear down the gaps.
    12" is quite deep to dig down, unless it was to get the right level

    The website pavingexpert.com has lots of advice
     
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  3. bigpepespunch

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    Thanks for the reply. You think it will be OK if I break up the rubble even more with a sledge hammer and then put the sand down? Yeah I know it's deep mate but the clay soil meant I was probably overly cautious
     
  4. scbk

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    I think you'd be best off putting more hardcore on top of the rubble and compacting that, to fill the voids
     
  5. bigpepespunch

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    OK mate il do that. Then how much sand would you recommend? And just normal builders sand?
     
  6. scbk

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    No you must use sharp sand. Building sand is too soft. You can do it with or without cement.
    Have a read of the paving expert website
     
  7. bigpepespunch

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    Thanks for all your advice friend.
     
  8. bigpepespunch

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    Hi guys have another question. Going to top the rubble with some more mot 1. The question is how high do I take the hardcore before I wacker it? Does it need to be level with the rest of the existing concrete or will it wacker down a few inches so needs to be higher and then wackered down ? If that makes sense? Cheers
     
  9. Halitosis

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    The more frequently you whack it the better the compaction (and less likely future settlement and sinking of your patio). Generally suggest a few inches at a time, plenty of whacking, then the next few inches and so on. In reality you probably wont see the level go down much at all, so for heaven's sake don't pile it high only to have to scrape/dig some back up. Big chunks appear to rise to the top during whacking (actually its the small grains sinking down into gaps) so any large stones should be put in first, and sharp sand last.
    Good luck driving the whacker - they're fun!
     
  10. nuzuki

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    Also use a bit of water to compact down the stone. I believe its called hydrocompaction although really its just water softening mud slightly so stones can be bedded in further. I used limestone scalpings for my patio base from earthline. It worked out about £20-25 per tonne but i think minimum order was 5tonnes.
     
  11. bigpepespunch

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    Thanks for the advice guys, its really helped.

    I do have another question im afraid :LOL:

    I have attached some pictures of the concrete that was original with the house (in the 80's) The concrete is the standard 150mm below the DPC as you can see. Is there any way i can slab over it without it being too high? would some gravel around the edge help or would the concrete have to come up?

    Thanks
     

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  12. Halitosis

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    Are you talking about mortaring your patio slabs on the concrete? If so then you're taking your ground up to approx. 100mm below the DPC - not ideal but shouldn't cause a problem. If going closer to/level with/higher than the DPC then the thing to do would be to build a dwarf wall 200mm out from the house wall, fill your void and slab over it leaving a dry moat (aka french drain) between the house and patio. That's how I did it, and our patio is level with the indoor floor level. Critical that the patio slopes away from the house so rainwater drains away.
    [​IMG]
     
  13. bigpepespunch

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    I was thinking that the slabs would be around 60 mm below the dpc, i would then leave a space of around 12 inche out from the wall and put gravel there? Is that a bad idea?
     
  14. Halitosis

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    12 inches is a lot more than necessary - my slabs are 4-5 inches out from the house and above the DPC - they breach the gap at door thresholds similar to any doorstep. A lot of people fill the void with stones, which probably looks nicer. On the downside, leaves, dirt, fag butts and other crud builds up within it, and you cant actually tell if its draining away or you've got 6 inches of festering water just out of sight soaking into your house bricks. Perhaps stones can prevent a foot going down the gap (a bigger concern if you have children about) but we've never had a problem and you'd have to make a conscious effort to place your foot that close to a wall :confused:.
     
  15. Anstiss Ltd

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    www.pavingexoert.com is a great resource when doing this kind of work.

    There is also a forum there that is useful.

    Check it out.

    Re DPC 150mm is recommended but you can drop this to 75mm
     
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