Coefficient of Lift

Under ideal conditions, coefficient of Lift is zero for a flat roof. Lift of a Flat Surface in Wind | UKEssays.com https://share.google/MFoQ01pnS1zIokU4F

But lift is high at low angle - from zero it increases by 0.1 for every degree - initially it's linear, maxes at 45 degrees at 1.

120 mph wind is 200 kg/sq meter.