Hey guys, new on this website, looking forward to learn!

So, as the title says, I'm using photoshop, and trying to build a battlemap.

My first mini learning project is a simple house.

I'm currently stumped upon a small shadowing problem inside the house.
Udklip.PNG

My primary problem is that I'm pretty sure there shouldn't be shadows inside of the house.

Another thing that puzzles me: an effective way to make walls? Floor is easy enough, but walls?
What I did was that I took the rectangle tool, and made a rectangle the size I wanted, and then used a Pattern overlay as well as Bevel & Emboss to make the walls look more realistic.
And to fit in the door I created a vector mask on the layer and deleted the part of the wall with a brush, that I didn't need.

All tips and help is greatly appreciated!
Cheers,
Helkor