I'am measuring some roofing plans for my buddy's building, on the blueprint the building is 67' x 80' which comes up to 5360 s.f now the pitch is a 6/12 is this the right ratio for a 6/12 1.118, so if i take 5360 x 1.118 = 5992.48 which is 60 squares is this right. So the building would be 6000 s.f correct or do i take the 5360 x 2 sides which is 10'720 sf . if anyone can help me this would be greatly appreciated. thanx