Raised Bluestone Patio

Discussion in 'Hardscaping' started by clandscaper, May 20, 2007.

  1. clandscaper

    clandscaper LawnSite Member
    Posts: 26

    I just got a call about a 20' x 20' bluestone patio and when I went out to look at the site it seems like a retaining wall along the front will be necessary because the large slope of the yard. I havent measured the exact grade yet, but I figure the front(side farthest from the house) will need to be elevated by no more than 1.5 ft, with the two adjacent sides starting at this height and decreasing to nothing towards the house.

    I figure I'll build the small retaining wall, dry-laid, and just line the inside with a fabric to keep the patio base material (crusher-run and stone dust) from leaking out.

    I have a couple questions. First, should I mortar the perimeter stones to keep them from shifting and to prevent stone dust from leaking out through the joints, and second, is this the best method that you guys know of for raised patios/terraces? Any other ideas? Thanks for the input
     
  2. Kate Butler

    Kate Butler LawnSite Senior Member
    Posts: 640

    First question - no, not necessary
    2nd question - it's always worked for me for walls less than 3' in height. I make a point of planting alpine perennials or sempervivums (hens and chickens) in the larger spaces between the stones: it looks much nicer than gaps in the stonework.
     
  3. clandscaper

    clandscaper LawnSite Member
    Posts: 26

    Sorry, I wasn't clear with my second question. Do I need to mortar the perimeter stones of the patio, not the retaining wall, to help keep the stone dust in-between the bluestones from leaking out the side of the patio and out the wall that they are on? I want to dry lay the wall, but would use mortar if necessary. Any input is appreciated. thanks
     
  4. Kate Butler

    Kate Butler LawnSite Senior Member
    Posts: 640

    I've never used stone dust as a finish between stones; always polymeric sand - so I can't speak to that question. I've also never used anything but medium sta-mat for my base BECAUSE of it's ability to REALLY compact and never move - even with out legendary frost heaves.

    Logically, though, if your base is sufficiently compacted, that shouldn't be a significant issue. However, crusher run and stone dust does sound like it has possibilities for seepage. I guess if it were me (using your spec'd materials), I'd compact my next-to-top run of base, lay some nonwoven (feltlike) geotextile, then the top layer of base, and set the bluestone. The reason I'm mentioning a layered base is because WITHOUT layering (putting down 4"-6" then compacting) and with a 1.5' depth differential from current existing grade (using crusher run and stone dust) you could have pockets of improperly compacted base that could affect the long term finish level of the project.
     

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