My screened porch is raised 48" and I am wanted to know the proper way to build my fireplace, specifically the firebox so that it is structurally sound. Because it is being built off the ground I want to know the proper way to support it. I hope this makes sense to someone. Thanks in advance for your help.
that's a good question for your local building inspector. I'm thinking the porch is actually a deck-like structure, and putting a gas fireplace in there is way below code and not acceptable.
a wood-burner is definitely out.
sig: if this is a new economy, how come they still want my old-fashioned money?
If I understand your question that you want to have the firebox at the same heigth as your screen porch floor. The method would depend on the type of fireplace you are going to erect. If it is wood burning does it have a prefabricated firebox or firebrick. If it is a mason structure then it needs to have a footing at ground level and then up with block to that level. If it is a fabricated then a wood frame constrtuction keeping withthe manufacturers recommendation of clearences.
If it is a gas fireplace then a wood or mason platform will work as long as you again keep with the manufacturers guidelines on clearences.
Maybe a clarification in your question might help.