Hmm. Strange. The lowest third of my barrel, and the bottom, are always cooler than the top 2/3rds. I use no bricks on the inside, btw. I was showing my 4yr old boy this just yesterday. While running at cooking temp I can touch and hold the bottom and the lower 3rd. But try to go any higher and you immediately have to jerk your hand back.
Don't get me wrong though, I'd never set it directly on wood. I space mine off my deck with bricks.
UDS, mini wsm