What you could do is use Duplifaces (a bit different from a simple Array + Curve as it won't distord your object):
Create a curve that follows the roof shape, put its origin at its beginning.
Create a plane, scale it as necessary, apply scale and rotation, make it follow the curve with Array + Curve modifiers.
Keep your plane selected and in the ...
It works better when you use the Curve modifier.
1) Go to Edit mode and rotate your mesh 90 degrees so it aligns better with the curve.
2) Set array modifier to Count or Length
3) Add a Curve Modifier and set the target to your curve.
Rotate your mesh in edit mode.
Set Array modifier to Count and add a Curve modifier
And here is the edited file....