A double pitch roof with different sides and angles is easy to construct with following workaround:

1. Create a single pitch roof and cut it at the apex. Enter the desired height and angle.

2. Create another single pitch roof on top of the first roof. Cut of the other side of the apex and configure again height and angles. 

Both roofs strikes at the apex. You do not have to place the roof in the middle and can define different length and angles.