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# Roof area calculation

## Roof area calculation

#1
11-07-06, 10:02 AM
Member
Join Date: Nov 2001
Location: Washington State
Posts: 86
Roof area calculation

Getting ready to roof my new addition. Is there an easy way to calculate the area. The addition has a gable roof: 25' x 28' with 16" overhangs and a roof slope of 8/12. Trying to figure out how many bundles of shingles to order.

#2
11-07-06, 10:27 AM
Group Moderator
Join Date: Dec 2004
Posts: 27,009
The easiest way is to actually measure the area to be roofed. Length x width = total area in sq. ft. Divide sq ft by 100 to get the total amount of "squares" Most shingles are 3 bundles to the square. And calculate some extra for waste.

If you can still see the plywood, you can guestimate how big the roof is based on the size of those 4x8 sheets.

#3
12-02-06, 01:34 AM
Member
Join Date: Dec 2006
Posts: 8
Originally Posted by CougGuy
Getting ready to roof my new addition. Is there an easy way to calculate the area. The addition has a gable roof: 25' x 28' with 16" overhangs and a roof slope of 8/12. Trying to figure out how many bundles of shingles to order.
Yep just measure the roof. 8/12 is not too fun to measure though. If it's a new addition you should have some plans to measure from.

#4
12-02-06, 09:30 AM
Member
Join Date: Feb 2006
Location: USA
Posts: 6,394
Roof

On an 8/12 pitch, 1.21 x horizontal distance will give the sloped roof distance.