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Roofing

The estimated roof area is 2,818 square feet

or 261.8 square meters or 313.1 square yards.

To have 10% buffer would require 31 roof squares.

By United States standard, the roof will need:

85 bundles of composition shingles (each bundle will cover ~33 ft2)

29 rolls of roll roofing (~36 in × 36 ft for each roll)

8 rolls of #15 felt (~36 in × 144 ft for each roll)

15 rolls of #30 felt (~36 in × 72 ft for each roll)

Roofing

To have 10% buffer would require 25 roof squares.

By United States standard, the roof will need:

67 bundles of composition shingles (each bundle will cover ~33 ft2)

23 rolls of roll roofing (~36 in × 36 ft for each roll)

6 rolls of #15 felt (~36 in × 144 ft for each roll)

12 rolls of #30 felt (~36 in × 72 ft for each roll)