Things You'll Need:
- Small notebook
- Pen
- Measuring tape
- Ladder
- Rope
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Step 1
Set the ladder up by the roof and climb onto the roof. Make sure you bring the notebook, measuring tape and pen.
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Step 2
Choose a section of the roof to begin. Make sure to measure one flat section at a time.
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Step 3
Attach the measuring tape to the bottom edge of the roof and walk straight up the roof to the peak. Write the measurement in the notebook.
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Step 4
Place the measuring tape on the side of the roof and stretch it to the other side. Record the measurement with the first measurement. For example, "measurement 1 x measurement 2."
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Step 5
Go to the next section of the roof that needs shingles and do the same measurement process. If you have a triangular section, measure the distance along the edge of the roof and the distance to the peak of the triangle from the center of the bottom edge. Make a notation of the triangle measurement in the notebook.
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Step 6
Exit the roof and put the ladder away.
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Step 7
Multiply the length times width measurements to determine how many square feet are in square and rectangular roof areas. For example, "17 x 23 = 391."
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Step 8
Figure out the area of triangular sections by multiplying the length of one side by the height of the triangle (the two measurements you have) and dividing the number by "2." For example, "17 x 10 = 170" and "170/2 = 85."
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Step 9
Add up all of the square footage numbers you have. For example, "391 + 391 + 85 + 120 = 987."
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Step 10
Add 10 percent to the square footage number to account for additional shingles you will need to purchase. These additional shingles will ensure you have enough scrap shingles, which you will need during installation. For example, "987/10 = 98.7 (round up to 99)."
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Step 11
Add the total square footage of the roof to the scrap shingles number. For example, "987 + 99 = 1086."
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Step 12
Divide the total square footage by 100 and round the number up for the total squares of shingles you need to purchase. For example, "1086/100 = 10.86" rounds up to 11 squares of shingles.









