Use stone slabs or slates to cover either side of the grill and attach the knobs for the fire valves. step 4: build the firebox for the fireplace or firebox, measure 29 by 29 inches from the base to the base of the arch to make the entrance.. When it comes to design, you'll have plenty of options for your outdoor fireplace with a grill, from traditional brick, stone and stucco styles to more modern granite and even metal models. if your plan is to hire a stone mason to build a custom-designed outdoor fireplace, you'll have total control over the look and feel, size and materials. Use these outdoor fireplace ideas to give your deck patio or backyard living room a dramatic focal point browse pictures of designs for, find and save ideas about outdoor fireplaces on designs ever an fireplace design brick is, prefab outdoor fireplace fire pit design ideas feature brick pictures..
