I am adding on a room to an existing frame- it used to be a screened in porch. I framed around the 4x4's and left the existing wood frame at the top (aprox. 12" all around the top) and butted the drywall up to it. Is the drywall mud going to join the wood to the drywall properly, or am I going to have to slap some trim up there? Please and thank you...:huh: