# How to Establish Your Yard Grade

Even a flat-looking yard probably has a slight slope in some direction; if it were perfectly flat, rainwater would not run off it. Determining the slope, or grade, of a yard is often necessary as a precursor to landscaping, altering the drainage or applying for a building permit, so it's important to get it right. Using only the most basic tools, it's possible to measure the grade just as accurately as a professional can do it, but at a fraction of the cost.

#### 1

Select the longest plank you can find; the longer it is the more accurate the results will be. Measure the length of the plank with a tape measure. Mark the position of the last complete foot on the upper surface of the plank. For example, if the plank is 7 feet 5 inches long, mark the 7-foot point on the plank, and if it is 9 feet 3 inches long, mark the 9-foot point.

#### 2

Refer to the marked end of the plank as "A" and the unmarked end as "B."

#### 3

Position the "B" end of the plank at the top of the slope in the yard. This is the point from which the gradient will be measured.

#### 4

Place a builder's level on the upper surface of the plank at the "A" end. Align it so it is parallel to the sides of the plank and in a position where you can see it while kneeling at the "A" end of the plank.

#### 5

Raise the "A" end of the plank until the builder's level indicates that the plank is horizontal. When this occurs, the bubble will rest at the center of the horizontal measuring vial.

#### 6

Keep the plank perfectly horizontal and, at the last foot mark, measure the vertical distance from the underside of the plank to the ground. For example, if the last foot mark was at 7 feet, measure the distance to the ground from that point, not from the actual end of the plank. Record this measurement; it's the distance the yard surface has dropped over the length of the plank.

#### 7

Convert the vertical distance obtained in Step 6 into decimal feet so that inches and fractions of an inch become tenths of a foot. For example, 1 foot 6 inches becomes 1.5 feet, and 2 feet 1 7/8 inches becomes 2.16 feet (see Resources).

#### 8

Divide the measured length of the plank by the vertical distance to obtain the grade. For example, if the plank is 7 feet long and the vertical distance is 0.5 feet, divide 7 by 0.5. The result, 14 in this example, is the distance over which the yard rises or falls by 1 foot. The grade is 1:14, a 1 foot fall over 14 feet.

#### 9

Convert the grade into a percentage, if required, by dividing the vertical distance by the horizontal one, and multiplying the result by 100. For example, 1:14 is identical to a grade of 7.1 percent because (1 / 14) x 100 = 7.1. Likewise 1:17.5 becomes 5.7 percent because (1 / 17.5) x 100 = 5.7.

References

Resources

Tips

- If the yard grade is irregular, repeat the process along the entire length of the yard, recording each section's grade. Add the grades together and divide by the total number of grade measurements to determine the average grade.

Warnings

- Make sure that the plank is stout and straight. Badly warped or flexible planks may distort the reading given by the builder's level.

Writer Bio

David Robinson has written professionally since 2000. He is a Fellow of the Royal Geographical Society and the Royal Meteorological Society. He has written for the "Telegraph" and "Guardian" newspapers in the U.K., government publications, websites, magazines and school textbooks. He holds an honors Bachelor of Arts in geography and education and a teaching certificate from Durham University, England.