The entire enclosure box of the fireplace has been constructed of cement block. The mason cut and shaped the fireplace opening into a self supporting arch. The upper arch is a continuation of this masonry structure supported with rebar reinforcing. The "trim" around the fireplace opening and top is a standard styrofoam form that is skim coated with plaster.

Thank you for your prompt reply, I guess our construction methods are slightly different in the UK. I like the concept of the double arch but I'm not sure how To construct this with the materials available here, guess I should stick to straight lines.

I believe that many of the construction techniques here in the US orginated in Europe and the UK. Don't feel that you have to sacrifice all esthetics for ease of construction. I suggest you consult with a professional (either a contractor, mason or architect) in your area for advice. The cost of some advice will be a very small percentage of the total cost of the project.

Hi - We are based in the east bay and are curious the construction team that executed the landscape/backyard work? Would you be able to share?