Enemy Spawning On My Roof

[Boredfan1]

So, for reasons I don't understand, enemies are constantly seeming to spawn on my roof. While my house isn't entirely walled, the top half is completely walled with a mix of mud and wood while only some of the bottom is walled with wood. My house isn't completely made of wood however as I have been having trouble getting wood due to problematic spawns outside my house at night and deaths that were ♥♥♥♥♥♥♥♥, wasting quite a bit of time. Those aside, a large portion of my roof and the walls of the second story are made of stone. I've watched other people play, hardcore in particular and they never had this problem with the exception of the boss summons. With my luck and this problem, I can't stay alive long enough to make any significant progress...(it's mostly zombies coming down the platforms that is causing me problems in regards to enemies spawning on my roof.) Anyways, thanks for any advice or information in advanced.

[Boredfan1]

Hmm. Okay, I'll try that, thanks again.