String Lines and Laser Levels

Discussion in 'Hardscaping' started by Graveslawncare, May 15, 2012.

  1. Graveslawncare

    Graveslawncare LawnSite Senior Member
    Posts: 472

    Hey guys, I need a crash course in string lines and laser levels. I know bits and pieces from classes and pictures and stuff but I still could use a better working knowledge of the procedures and how they actually tie in to building a hardscape. What are all the steps from setting up a laser level to using it to pitch the patio? Where do you put your string lines and how do you apply them to the construction in various applications? Things of that nature.

    I also thought this info would be good for anyone else who was on the learning curve too. This is where I am a strong believer that no amount of icpi, ncma, (I have both), supplier classes, trade shows, etc can be substituted for good 'ol experience. And since I'm still working on the experience part, I tend to go ask guys who already have it figured.

    So have at it, tell me everything you know, post illustration pics, links, whatever. Thanks in advance for the help.
     
  2. neversatisfiedj

    neversatisfiedj LawnSite Bronze Member
    Posts: 1,028

    Shoot your closest elevation to the house say it reads 8'0 on the story pole. Say you want a 2% pitch on the patio for rain water. Now measure where the end of the patio is going to be. Say it's 15' out ftom where you took your last reading. Take 15' x 12" to convert to inches = 180, now x that by .02 to get the amount you have to drop the patio. That = 3.6 inches. So you read 8' at the house, your story pole should beep at 11.6" to give you your desired pitch. Bang your stake and stringline collar at that elevation.
     
  3. Graveslawncare

    Graveslawncare LawnSite Senior Member
    Posts: 472

    So using this technique you measure down from that string line to check your base, right? How do you go about checking in the middle though? Away from the edges of the excavation? Do you or anyone else on here run any other string lines? I've seen guys say that they run them to keep bond lines straight, but the demonstrations I've seen used chalk lines snapped on the screeded sand. That made more sense to me because that can't move like a string, and it's not in the way. Keep 'em coming, I would like to hear/see a few different examples of the way you guys do things.
     
  4. alldayrj

    alldayrj LawnSite Gold Member
    Posts: 3,774

    When i use them to keep bond lines straight i keep them up off the pavers so they don't get hung up and give a false reading. Don't let guys stack pavers on the string!
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  5. AztlanLC

    AztlanLC LawnSite Bronze Member
    Posts: 1,046

    We haven't used string lines to check for elevation in such a long time they are a pain to work around, most is done with the laser level and a good eye. this year I might get a laser with slope feature.
    We shoot the elevation at the highest grade and then raise 1" the detector every 5" toward the pitch of the patio, keep digging and checking once in a while (this is where you need a person with a good eye) repeat the process to install the base material.
    We always find a structure like a existing footing, make a mark on the foundation or drive a rod to set a reference point for our starting grade, that way in case we don't finish that day or have to move the laser we know what it has to be regardless where we position our laser.
     
  6. neversatisfiedj

    neversatisfiedj LawnSite Bronze Member
    Posts: 1,028

    Just cross the stringlines in the middle. Screed your base in with your gas pipe
     
  7. Graveslawncare

    Graveslawncare LawnSite Senior Member
    Posts: 472

    This is great! This is the kind of discussion I was hoping for :drinkup:

    Did you mean you raise the detector 1 inch for ever 5 FEET? Do you just rely on your eye to know that the slope is consistent from the highest point to the lowest point of the excavation/base?

    Here is another question for you guys that has been bugging me for a while. In some guys' job progress pics that I have seen on this site, I have seen guys with a level on top of their screed rail checking it before they set it in place and screed. This did not make sense to me because since the patio should have at least a 2% pitch, nothing should be level, right? So why are these guys doing this? Are they perhaps checking to make sure that it's NOT perfectly level?
     
  8. neversatisfiedj

    neversatisfiedj LawnSite Bronze Member
    Posts: 1,028

    I keep mine where I can level from left to right and pitch out from the hose. I also use a level on my screed pipe when I will install base.
     
  9. Graveslawncare

    Graveslawncare LawnSite Senior Member
    Posts: 472

    Gotcha, so if I'm understanding you correclty, you screed perpendicular to the pitch of the patio, in which case your screed rails should be level?
     
  10. neversatisfiedj

    neversatisfiedj LawnSite Bronze Member
    Posts: 1,028

    yep. The lines will get in your way , but higher you come up with your lifts the easier it will get. Just run the compactor over them. I use these http://stringalongcollars.com/
     

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