Yeah more than a box :)
I'm upgrading and changing a house that came with the game. The lot name is "Streamlet Single" it's in the cheap district of Willow's Creek. I added an upper floor to it and opened up the kitchen into the livingroom. Else I haven't changed the floor and even closing off the kitchen agian does not change this. Other than opening the kitchen and placing a stair near the front door I haven't changed the bottom floor.
The issue is happening at the back right wall of the main box (not the kitchen box) where the wall has a corner, then goes forward one tile and takes a right turn into the kitchen.
It's on this corner where it's refusing to show the siding.
Hold on gonna try figure out a way to upload a picture of this.