both sides extrude and duplicates problem

Hi
I'm newbie in GH and this is my first try to assemble building structure by algorithm and i met some problems.
In the whole pipeline i had alot of duplicate objects but in the uploaded algorithm i have clear most of them. I cant extrude the builded surfaces both sides without produce a lot of duplicate polysurfaces.I need clear and light model ,convinient for archicad connection and rendering for future.
 I have tryed few tutorials to get rid  of the duplicates , but without success so far.I cant figure out where is my misstake and how to fix it.
I appreciate any help from you.
Thanks in advance !