making a two sided fireplace
Hi all, I have a one story ranch with a fireplace in my den. The backside of the fireplace and chimney are outside and run up the exterior back wall. Right where the backside lies is where my outside seating area and patio is, so here's my plan:
Cut a hole into the backside of the fireplace to make it a two sided fireplace, one outside and one inside. I would install steel doors on the outside for when it's not in use and winter.
My questions: Are there any structural problems with cutting hole into the fireplace? Is a header needed? I'm very knowledgeable in construction, just never really did much masonry work. Thanks for any replies.