I have just installed a 550 Rockland in a double sided fireplace. The problem I am encountering is that there is a one inch space between the brick face and the top of the 31x40 cast iron surround. There also is a space that decreases from top to bottom( where there is no space) . It appears that the insert itself is not flush with the brick hearth face. How can I fix this? My setup is exactly like the one on the cover of Jotul's brochure. Any help is greatly appreciated. Also any thoughts on its ability to heat an 850 square foot room with an eight foot ceiling?