Splitting and/or boolean

Hi guys

I want to split my roof for so that i have the shape of the extruded surface opened up on my roof . However for some reason split doesnt work or boolean im not sure what to do really.<img src=“https://aws1.discourse-cdn.com/mcneel/uploads/default/original/3X/2/d/2d649b79dea8eb56214a12074cca99827b810b00.png” width=“690” height="431"e

Hard to tell without a file.
If you create the intersection between the two, what do you get - i.e. is the resulting intersection curve a closed curve?

I managed to get it done,the wall wasnt closed of properly but thank youuuu