Fire surrounds can either be used with electric insert Fires or a gas insert Fires. Some fire surrounds are suitable for solid fuel fires (this involves burning real cold or logs). The majority of fire sounds are suitable for Electric Fires and gas Fireplaces, however require customisation to be suitable for solid fuel fires (to accommodate the intense heat created while burning solid fuel). Gas Fireplaces required 25mm rebate in order to create an airtight gap between the back of the wall and the fire surround. This means that the marble back panel is pushed against the wall with an Infill piece of marble please see diagram. The additional strip of marble pushes the back panel against the wall and makes it easier to create an airtight gap. The majority of experienced gas engineers can fit a inset gas fire and surround with a larger rebate (eg a 75mm rebate), however 25mm rebate makes it significantly easier to install a gas fireplace.