I have a prefab fireplace (Martin SB4800) which is a decent sized fireplace and will actually fit a Jotul 550 Rockland. However I know the weight of the Jotul is heavy at 550lbs and am curious if my prefab can hold this weight? Does anyone know or can find out more on how my fireplace base is constructed? Will it hold the weight? Anyone else have a Jotul 550 in a prefab zc fireplace?