base and pitch

Discussion in 'Landscape Architecture and Design' started by hewitt64, Apr 1, 2002.

  1. hewitt64

    hewitt64 LawnSite Member
    Posts: 43

    Do you guys set the pitch for drainage of the patio with the base or do you do it when you do the final screed with stone dust?
     
  2. Lanelle

    Lanelle LawnSite Bronze Member
    Posts: 1,361

    Your base should be perfect for pitch and surface. Any imperfection will telegraph to the pavers eventually. Also, sand is the recommended screed material according to most manufacturers and the ICPI. (I know there is some dissent on this.)
     
  3. hewitt64

    hewitt64 LawnSite Member
    Posts: 43

    So does that mean that you have the pitch in the base not the screeding part
     
  4. diginahole

    diginahole LawnSite Member
    Posts: 249

    That's correct hewitt. Base should be to the appropriate grade (min 2% away from structures) before insalling bedding sand. The surface tolerance for base is +- 3/8" measured with a 10' straight edge. Bedding sand should be screeded to a uniform thickness, and never used to correct imperfections in the base.
     
  5. Stonehenge

    Stonehenge LawnSite Bronze Member
    from Midwest
    Posts: 1,277

    Yes, never use sand to correct base imperfections....except of course for the +- 3/8" (or 3/4" total possible variance) imperfection... :D
     
  6. diginahole

    diginahole LawnSite Member
    Posts: 249

    Actually, it's read plus OR minus not plus AND minus, so the maximum variance remains 3/8". Man... I'm getting picky in my old age LOL.
     
  7. PAPS

    PAPS LawnSite Senior Member
    Posts: 404

    The problem with using the "screeding" part as a final pitch, being stonedust or sand, is that you may have some areas once done screeding, that have more than the 1'' of sand recommended., IE. the patio is sloping and the top has the nec. 1'' of sand, but the bottom has like 2-3'' of sand for the adjusted pitch.
     
  8. Stonehenge

    Stonehenge LawnSite Bronze Member
    from Midwest
    Posts: 1,277

    Hey, I'll get picky with you....

    "plus or minus" typically means deviation in either direction from a specific measurement. Like "It'll cost you 5 grand, plus or minus a few hundred bucks."

    So over a given area, there could be a 3/8" dip in one spot, or 3/8" hump in another, or a total of 3/4" total variance. Or it'll cost you anywhere from $4700 - $5300.

    Or are you saying your tolerance is really +- 3/16", or 3/8" total?
     
  9. diginahole

    diginahole LawnSite Member
    Posts: 249

    duuuuh, I don't know. I usually just set strings and bring the base exactly to them. After compacting I check it with my 7' level and repair ANY high or low spots until there isn't any daylight showing anymore.

    Sidenote: areas that have been filled or scraped down need to be recompacted.
     
  10. Stonehenge

    Stonehenge LawnSite Bronze Member
    from Midwest
    Posts: 1,277

    Do you set strings to the top of your base, or the top of your pavement?

    The reason I ask is, we use levels that are within 1/4" the height of most pavers, and helps us to get things close before we set our screed pipe.
     

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