The part where it hits the roof...you should be able to see a thick layer of mortar where you couldn't add any more stones, and the stones should be very irregular in that area. That's what's the problem there. But I also agree that maybe the stone wall needs to be individually mapped, or displaced. I realize it could be an enormous pain...but the few comments about it are right: It just doesn't look quite right.
Also, the platform supporting the balcony...what kind of material is it? It DOES need some variation in the color. Even if it's painted, it wouldn't look that smooth under direct sunlight.
arch4d: I used Full IOR Chromium and set the roughness to 25.
daros, NicoR44: Coming from you guys that really means alot.
u.big : Displacement would be very nice to have
tom: the king of leveling
yadikrisnadi, Mattia Sullini Thanks you very much
carlos: I will post material setting later for you...
jonathan löwe, CJElven: didn't even look at that thank for pointing it out to me.
iker: Thank dude...