The way I solve this problem is through a series of two equations. The equations are
Vf = Vo + gt (1)
and
x = Vo*t + 0.5*g*t^2 (2)
where Vf is the final velocity
Vo is the initial velocity (equal to zero)
g is the acceleration due to gravity
t is the time of travel
x is the distance traveled.
The first eqn is used to calculate the time it takes to reach the bottom. Therefore, substituting value to eqn 1, we get
185 = 32*t
t = 5.78 s
The second equation can be used to calculate the height of the roof
x = 0.5*32*5.78^2
x = 534.53 ft
hope this helps