I would need some help with an asymmetrical roof form

[heAd3r]

hi, Im working on a project that has a certain amount of irregularities. One of those is the roof. As can be seen on the images, the roof is asymmetrical and slightly angled towards the back. When I try to create a roof over it I always get that weird curve as can be seen in the other image. Is ther a certain way to approach roofs like that?
I used the roof tool and added the rising points manually. 

thanks in advance.

[msgambelluri]

Could you explain your problem further?
What is undesirable when you create the roof via "roof tool …. And rising points manually"? Could you point out that “weird curve” in the image?