how do i figure out the Sq. Feet for my roof?

Question

i have all the numbers but what do i do now?

Answer 1

Width times length =square feet-A rectangle 20 by 40 has 800 sf Chop the roof up into rectangles and then add them together

Answer 2

Once you calculate the square feet of roofing, divide that number by 100. Roofing is sold in SQUARES (100 square feet). If you will be using asphalt shingles it will require three bundles of shingles per square.

Answer 3

Calculate the sq footage with the numbers you have.
Then add an extra sq.f. for every linear foot of ridgeline.

Also make sure you order ridgevent and flashings.

Answer 4

Measure the length of the roof. (You can do this from the ground)

Measure to the centre of the width.,

Add half the height from the gutter, to the apex.

Multiply this by the length and then by 2.

Answer 5

try to divide the roof in simple geometrical figures (triangles, rectangles)
then use their dimensions to calculate each separate area...
for triangle area=base * height / 2
for rectangle area=lenght * width
then just add the results together...