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NW Ohio,near Findlay | Where I worked we did lots of main replacements that were broken down, washed out in waterways that have changed. We had a lazer that we used at that time that you could bypass the auto level mode and manually set grade. Yes we would expose the lower and upper ends and try to estimate distance and manually tilt lazer, walk the distance and check. We also made sure to come in just a little low to hook up. Some rotating lazers can be set to run out of level to match your end grade, BUT BE CAREFUL. You can be set up perfect and if anything moves that lazer, wind, ground thawing out, you are screwed, a little movement can totally give you false readings. While trenching, keep checking the high end to make sure lazer hasn't shifted.
This happened to us ONE time. Put in over a 1000 feet of 8 inch, got to end and too high Had to go back and find a grade low enough to work, flatten out and redo with backhoe. No room to move over and use trencher. Tried to figure out what happened, who screwed up, misread distance. Finally figured out tripod was set on frozen ground and during day the sun melted and the points settled just enough to change grade. On a lazer that we manually set slope to match end was the problem. A lazer that you set the percentage, IF it settles, your percentage will reset,( may shutoff to reset ) but you will know it or will come in a little low. Hope it never happens to anyone else. Pitched that modified lazer level, never made for tile work, and never used again. | |
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figuring grade or slope for tiling
