We are wanting to put in a pellet insert into our fireplace, plus also lower it. We have a fireplace, that has prefab/metal (cast iron or aluminum - not sure exactly. I believe that it is surrounded by wood framing. The chimney is metal pipe. The Hearth is a rock facad. Would this be an easy job to re-frame the space for the firebox? The opening seems also not as call as a standard box.
It wouldn’t be that big of a job to re-frame the fireplace if you currently have a pre-fabricated fireplace in use.
You most likely will replace the entire unit rather than installing an insert into the existing unit. Most of the pre-fabricated units that I am familiar with cannot be modified.
Before you do anything, I would decide upon the new unit you wish to install. Select one that fits your particular needs in terms of heat output and size.
Remove the stone and front framed wall of the fireplace and the unit will be exposed. Plan on replacing the flue when installing the new pellet fireplace.
Frame for the new unit, install per the manufacturer’s instructions, cover the framing with drywall and finish it off with a façade of your liking.