Hi,
I have a new beardie, the vivarium is wood, 36" long, 24" wide, 16" tall (inside floor to ceiling).
I have a new 24" T5 fixture for the UVB mounted on the inside of the vivarium, it is about 2" tall, so there is about 14" from the floor to the UVB bulb.
My beardie likes to bask on a log...