you have to have a way to either measure elevations from high end of square to the low end i.e. a laser level or just get a string level and set it on your string so that you get about an 1/8 of the bubble over the line so the slope is going the right way. This is very simple and you will figure it out with $5 worth of tools, string and level.

 

First figure your drop, length in inches times .02 for 2%. Set your stringline level and then lower one end that same amount. Easy enough?

 

We used to use a string line and line level with the 1/4, 1/4, 1/2" slope indicators. It worked pretty well. We then went to a transit and marked out x amount and feet and calculated what the measurement should read. That worked well.

We have since upgraded to a self leveling dual grade laser level. We haven't used it yet but from what I here its pretty darn simple.

 

To calculate slope just take a measurement in feet. Example Your patio is 20 feet in length. Convert to feet to inches. 20x12=240 inches. Now calculate a 2% slope . 240x.02=4.8 inches. So your grade marker at the lowest point 20 feet out on the patio should be 4.8" lower than the starting elevation to give your patio a 2% slope for drainage.

 

2% is pretty high for a paving slope, For streets and paved areas if I remember my college correctly, 1% is sufficient, and 2% for grassed areas

 

I tend to agree.I usually shoot for a 1% grade.

 

Okay I think I get it now. So you set the 2 stakes, one closest to the house (the high point) and one at the end of the patio. Then you figure out how much your drop of is by multiplying the length of the patio by either 1% or 2%, and then move the string line at the end down by that much.

Do you guys set out several stakes over the entire project? So if I am building just a square patio, I could set up 2 stakes (one near house, and one at the end of patio) at different intervals along the entire project?

So what I would do is excavate from the string line, down 9 inches (6 inch gravel + 1 inch sand + 2 3/8 inch paver) and take measurements with a measuring tape along the entire string line so that I get 9 inches down to the ground once I've excavated? And then once I add the gravel, and take the measurement from string line down to the ground I should have a measurement of 3 inches along the entire string line (for sand +paver)Hopefully I have that right

 

9" is a little on the shallow side, especially if you are in ottawa, it is mostly clay and you should aim for 12" depth, with geo textile.

 

10 foot pipe with a 6 foot level on top that has multiple lines on it. when you are touching the second line you are 1" on 10' witch is plenty enough for a patio.

 

use a line level on a tight line make it level then multiply out your pitch to determine how many inches to drop the line. if you want a 2% pith (1/4 per foot) and your patio is ten feet. Take 10/4 = 2.5 inches and lower one end down and it will pitch 2% over the ten feet.