Whats best way to model a room?

I want to do a lighting test but have had problems with odd behaviour of light at floor/wall boundary, one is brighter than the other.
Should I…
-Make the room from one object and multiple materials
-Use only front faces for walls or
-Use boxes to exclude light leaking (read that this is a problem at corners)

Previously I made a cube and deleted a couple sides then cut it up with windows and doors, applying multiple materials as I went. but this sux for flexability in adding geometry.

And what is the go with the shear tool? I got it to work once on a wall end but when I went to turn the wall back at the next corner, it would only shear in the vertical. How do you make the shear tool go the way you want?

Has anyone got good blender tuts for archi modelling?