# How much extra to add for pitch

#1

LxW not much over hang is there a certain amount you add for 7/12 pitch?

#2

as in, as the pitch increases, so does the roof area? i always add a square anyhow but i want to know if there is a true way to figure for the pitch increase.

#3

How about measure the roof. get the rafter lenths. when im in a hurry sometimes I will count the tabs. there is also a slower install in steeper pitches obviously.

#4

??? @ jason
Huh!?

#5

I like to go up on the roof and whip out the old tape measure or measuring wheel and do it the old fashioned way. THis way I get to check site conditions and help my customer to make informed long term decisions.

#6

why would a 20 foot rake edge be different on a 4/12 pitch as opposed to a 12/12 pitch. its still 20 feet.

#7

Lol, 20 x 20 is still 20 x 20 no matter if it’s a wall, floor, ceiling or a roof pitched at any angle.

#8

No its not, the foot print of a building is almost never the square feet of the roof area. the pitch makes for a longer rafter lenth. overhangs, hips valleys and dormers all make a difference. common sense and basic math really is all it is.

#9
``````Correct.
``````

If you run a tape on the roof you don’t need to calculate the pitch, if you use the footprint from the ground then you you do.
2-12= 1.014
3-12= 1.031
4-12= 1.054…etc

Google “roof pitch calculations” and the multiplication table will come up.

#10

He’s trying to figure out the formula to estimate the roof area based on the floor area. Thats why he said
"not much overhang".

Guys like this always under estimate, under charge,
hurting their own business and the others around them.

You have to get up on the roof and be a roofer before you really know how much material you really need and how much to charge.

#11

I’ve never measured a roof via building footprint then did calculations haha.
I just get up there and measure the roof… that way you can see what needs to be done, if there’s 1 or 2 layers of roofing, if there’s any rotted wood, if the flashing is shot, check out the condition of the chimney and its mortar cap and count the pipe flanges needed.
With this method I’ve never needed to add nor subtract due to pitch.

#12

[quote=“Adept Roofing”]I’ve never measured a roof via building footprint then did calculations haha.
I just get up there and measure the roof… that way you can see what needs to be done, if there’s 1 or 2 layers of roofing, if there’s any rotted wood, if the flashing is shot, check out the condition of the chimney and its mortar cap and count the pipe flanges needed.
With this method I’ve never needed to add nor subtract due to pitch.[/quote]

That is the best way IMO

#13

i cant get up on the roof guys. all i have is blue prints .LOL!

#14

leave jasonmhornbeck alone !
LOL

#15

cant get on the roof?

sounds like you need either a new job, or pay for xactamate then learn how to sketch.

why cant you get on the roof? too scared? dont own a ladder?

#16

[quote=“Agape”]

cant get on the roof?

sounds like you need either a new job, or pay for xactamate then learn how to sketch.

why cant you get on the roof? too scared? dont own a ladder?[/quote]

he means…there is know roof…the house hasnt been built.

#17

oh!

lol.

then just give me the measurements and the pitch, and i can throw it into xactamate for you and give you the # of squares

#18

The ones we price that are not yet built are simple to do material takeoffs with a scale rule. Most prints are made to scale. had two come fedex this week, very cut up but its in a high rent district.

#19

Ya. but the elevations are at 5/12 they changesed the actual to 7/12 to make the house apear bigger.

#20

And roof lover, i am not trying to under estimate if you would read the complete thread, im trying to get exact as possible because i am really not trying to under bid! Its guys like u that always have to run back to the supplier because they fell short!