Measuring Instructions
The fireplace opening dimensions needed are the width and height of the area that will not be covered by stone.
For prefabricated fireboxes: The black flashing around the firebox can be covered with stone.
If the firebox has a glass front, it cannot be covered with stone. Also, enough space must be allowed to remove the glass if necessary.
Some models have louvers for ventilation above and below the opening. These cannot be covered with stone.
Some models may have an access panel (usually below the firebox) which opens for access to a regulator for the gas. It cannot be covered with stone.
For masonry fireboxes: Make sure that all the brick is covered with stone. If necessary, we can extend the mantel an inch of two inside the firebox opening.