Caldwell has been a major part of the back four which has kept four consecutive clean sheets in the npower Championship, and admits he is enjoying life at St Andrew's since leaving Wigan this summer.
But he is conscious that the Blues must also perform at the other end of the pitch after their 0-0 stalemate with Brighton on Saturday.
"We've got a very solid shape so it's really enjoyable to defend in this team," he told Birmingham's official website.
"I think it's the base for us to push on now and impose ourselves on games.
"So far we've put a lot of reliance on Jean (Beausejour) and (Chris Burke) Burkey and the boys at the top to score goals but I think as a team we need to make angles and space for each other better and actually control a match."