Building and Carpentry

Math and Arithmetic

Interior Design

# How do you find the square footage of a roof?

###### Wiki User

###### 2015-10-27 19:15:04

To find the sq. ft of a roof you have to measure the length and

the width and multiply those figures together. Then you divide that

figure by 100 and it will tell you how many squares of shingles it

will take to cover it.

## Related Questions

###### Asked in Building and Carpentry, Math and Arithmetic, Area

### Your house is 1350 square feet how many shingles do you need?

The square footage of your house is not the same as the square
footage of your roof if there is any pitch. If you are asking
aboutasphalt shingles, generally each bundle covers 33.3 square
feet. Therefore find the square footage of your roof, divide it by
33.3 to find the number of bundles, then multiply the original
square footage by 5-10% to get the number of additional bundles for
cutoffs and starter strip. The variation in percentage accounts for
the number and length of valleys of the roof. Example:[@5%]
roof =1500 ft2 --> (1500/33.3=45.05) (1500x.05=75
-->75/33.3=2.25)
45.05 + 2.25= (48) bundles

###### Asked in Building and Carpentry, Plural Nouns

### How many roof tiles are there are on a roof?

That really depends on several different variables including the
square footage of the roof itself and the size / type of the tiles
being used.
Most of the time when buying roofing tiles / shingles it will
state on the packaging how many square's it will cover. It should
also state the "square footage" covered as well.
So once you have your square footage you can then figure out how
many tiles / shingles it will take to cover your roof.
Don't forget to add 10 to 15% for waste in your
calculations.

###### Asked in Building and Carpentry, Math and Arithmetic, Algebra

### My home is 1100 square feet what is the roof's square footage?

You cannot calculate the square footage of a house roof like
this (unless you have a flat roof). The simplest way would be to go
up on your roof and measure its different surfaces, however if you
dont want to do that, you would need to know several differen
things to calculate the surface area -- such as the pitch and angel
-- how much hangover you have.
Basically you should save yourself time and go up on your roof
and measure it

###### Asked in Building and Carpentry

### How do you figure roofing number of squares on roof?

You measure the roof to get the square feet. There are 100
square feet in a square. On a straight single peak roof it's height
times length on one side and double it. Then divide the total
square feet by 100. This final number will give you the number of
squares you have.
If the roof is a flat, commercial roof, it is the same (100 sq.
ft = 1 SQ). However, if it is a metal panel commercial roof, you
need to add in "stretch factor" or the added amount of square
footage if the panels were to be stretched flat. A good estimate
for this is: If the ribs on the metal panel are 1" tall, add 10% to
your square footage; if the ribs are 1.5" tall, add 15% to your
total square footage. So, if you have a metal roof that is an
R-panel (_/-\_), the ribs are 1.5" tall and the roof is 100 SQ (or
10,000 sq ft), take 10,000 sq ft + 15% (1500) = 11,500 sq ft (115
Squares).